{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-112880", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-10-26T10:15:01.166Z", "datePublished": "2026-10-26T13:48:46.589Z", "dateUpdated": "2026-10-26T15:35:50.632Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_http_connect"], "packageName": "hackney", "packageURL": "pkg:hex/hackney", "product": "hackney", "programFiles": ["src/hackney_http_connect.erl"], "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "4.9.0", "status": "affected", "version": "2.0.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_http_connect"], "packageName": "benoitc/hackney", "packageURL": "pkg:github/benoitc/hackney", "product": "hackney", "programFiles": ["src/hackney_http_connect.erl"], "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "5ee7d7d19eba27e774667d472feb1e93a08af7f9", "status": "affected", "version": "5df5a74a2817d5b12880d217db33253ff1fae1b5", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>The client connects through an HTTP CONNECT proxy with the <code>proxy_auth_fun</code> option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without <code>proxy_auth_fun</code>, or whose callback returns a fixed credential, are not affected.</p>"}, {"base64": false, "type": "text/markdown", "value": "The client connects through an HTTP CONNECT proxy with the `proxy_auth_fun` option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without `proxy_auth_fun`, or whose callback returns a fixed credential, are not affected."}], "value": "The client connects through an HTTP CONNECT proxy with the proxy_auth_fun option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without proxy_auth_fun, or whose callback returns a fixed credential, are not affected."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.9.0", "versionStartIncluding": "2.0.0", "vulnerable": true}], "negate": false, "operator": "OR"}], "operator": "AND"}], "credits": [{"lang": "en", "type": "finder", "value": "Daniel Coles"}, {"lang": "en", "type": "reporter", "value": "Daniel Coles"}, {"lang": "en", "type": "remediation developer", "value": "Benoit Chesneau"}, {"lang": "en", "type": "coordinator", "value": "Jonatan M\u00e4nnchen / EEF"}], "dateAssigned": "2026-10-26T10:18:44.000Z", "datePublic": "2026-10-25T00:00:00.000Z", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in <code>hackney_http_connect</code> in benoitc hackney allows HTTP Request Splitting via the value a <code>proxy_auth_fun</code> callback returns. After a 407 response from an HTTP CONNECT proxy, <code>hackney_http_connect:handle_proxy_auth/11</code> calls the caller's <code>proxy_auth_fun</code> with the status code and the response headers and writes the returned binary into the <code>Proxy-Authorization</code> line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.</p>\n<p>The value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.</p>\n<p>This issue affects hackney: from 2.0.0 before 4.9.0.</p>"}, {"base64": false, "type": "text/markdown", "value": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in `hackney_http_connect` in benoitc hackney allows HTTP Request Splitting via the value a `proxy_auth_fun` callback returns. After a 407 response from an HTTP CONNECT proxy, `hackney_http_connect:handle_proxy_auth/11` calls the caller's `proxy_auth_fun` with the status code and the response headers and writes the returned binary into the `Proxy-Authorization` line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0."}], "value": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller's proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0."}], "impacts": [{"capecId": "CAPEC-105", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>A party who controls what the application's <code>proxy_auth_fun</code> returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy.</p>"}, {"base64": false, "type": "text/markdown", "value": "A party who controls what the application's `proxy_auth_fun` returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy."}], "value": "A party who controls what the application's proxy_auth_fun returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy."}]}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "baseScore": 2.1, "baseSeverity": "LOW", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-113", "description": "CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-10-26T13:48:46.589Z"}, "references": [{"name": "hackney 4.9.0 release notes", "tags": ["vendor-advisory", "related"], "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0"}, {"name": "EEF CNA record for CVE-2026-112880", "tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-112880.html"}, {"name": "OSV record EEF-CVE-2026-112880", "tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-112880"}, {"name": "Refuse CR/LF/NUL in the proxy_auth_fun result (benoitc/hackney#989)", "tags": ["related"], "url": "https://github.com/benoitc/hackney/pull/989"}, {"name": "Introducing commit 5df5a74 in benoitc/hackney", "tags": ["related"], "url": "https://github.com/benoitc/hackney/commit/5df5a74a2817d5b12880d217db33253ff1fae1b5"}, {"name": "Fix commit 5ee7d7d in benoitc/hackney", "tags": ["patch"], "url": "https://github.com/benoitc/hackney/commit/5ee7d7d19eba27e774667d472feb1e93a08af7f9"}], "source": {"discovery": "EXTERNAL"}, "title": "CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Check the value your <code>proxy_auth_fun</code> is about to return for CR, LF and NUL bytes and return <code>{error, Reason}</code> instead when one is present. The callback runs in the application, so the check can be made there.</p>"}, {"base64": false, "type": "text/markdown", "value": "Check the value your `proxy_auth_fun` is about to return for CR, LF and NUL bytes and return `{error, Reason}` instead when one is present. The callback runs in the application, so the check can be made there."}], "value": "Check the value your proxy_auth_fun is about to return for CR, LF and NUL bytes and return {error, Reason} instead when one is present. The callback runs in the application, so the check can be made there."}], "x_technicalAnalysis": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p><strong>1. Challenge.</strong> <code>hackney_http_connect:do_handshake_with_auth/9</code> in <code>src/hackney_http_connect.erl</code> sends the CONNECT request to the proxy. When the proxy answers 407 and the <code>proxy_auth_fun</code> option is set, it hands the status code and the parsed response headers to <code>hackney_http_connect:handle_proxy_auth/11</code>.</p>\n<p><strong>2. Callback result.</strong> <code>handle_proxy_auth/11</code> calls the caller's <code>proxy_auth_fun</code> with those two values. On <code>{ok, AuthHeader}</code> it removes any existing <code>Proxy-Authorization</code> header and appends the binary <code>&lt;&lt;\"Proxy-Authorization: \", AuthHeader/binary&gt;&gt;</code> to the header list, then retries the handshake with it.</p>\n<p><strong>3. Splitting.</strong> The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside <code>AuthHeader</code> therefore ends the <code>Proxy-Authorization</code> line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same <code>has_ctl_bytes/1</code> check to it and returns <code>{error, {proxy_auth_error, invalid_header}}</code>.</p>"}, {"base64": false, "type": "text/markdown", "value": "**1. Challenge.** `hackney_http_connect:do_handshake_with_auth/9` in `src/hackney_http_connect.erl` sends the CONNECT request to the proxy. When the proxy answers 407 and the `proxy_auth_fun` option is set, it hands the status code and the parsed response headers to `hackney_http_connect:handle_proxy_auth/11`.\n\n**2. Callback result.** `handle_proxy_auth/11` calls the caller's `proxy_auth_fun` with those two values. On `{ok, AuthHeader}` it removes any existing `Proxy-Authorization` header and appends the binary `<<\"Proxy-Authorization: \", AuthHeader/binary>>` to the header list, then retries the handshake with it.\n\n**3. Splitting.** The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside `AuthHeader` therefore ends the `Proxy-Authorization` line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same `has_ctl_bytes/1` check to it and returns `{error, {proxy_auth_error, invalid_header}}`."}], "value": "1. Challenge. hackney_http_connect:do_handshake_with_auth/9 in src/hackney_http_connect.erl sends the CONNECT request to the proxy. When the proxy answers 407 and the proxy_auth_fun option is set, it hands the status code and the parsed response headers to hackney_http_connect:handle_proxy_auth/11.\n\n2. Callback result. handle_proxy_auth/11 calls the caller's proxy_auth_fun with those two values. On {ok, AuthHeader} it removes any existing Proxy-Authorization header and appends the binary <<\"Proxy-Authorization: \", AuthHeader/binary>> to the header list, then retries the handshake with it.\n\n3. Splitting. The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside AuthHeader therefore ends the Proxy-Authorization line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same has_ctl_bytes/1 check to it and returns {error, {proxy_auth_error, invalid_header}}."}]}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-112880", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-26T15:00:47.038622Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-26T15:35:50.632Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-112880", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-26T15:00:47.038622Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-26T15:32:18.053Z"}}], "cna": {"title": "CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney", "source": {"discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "Daniel Coles"}, {"lang": "en", "type": "reporter", "value": "Daniel Coles"}, {"lang": "en", "type": "remediation developer", "value": "Benoit Chesneau"}, {"lang": "en", "type": "coordinator", "value": "Jonatan M\u00e4nnchen / EEF"}], "impacts": [{"capecId": "CAPEC-105", "descriptions": [{"lang": "en", "value": "A party who controls what the application's proxy_auth_fun returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy.", "supportingMedia": [{"type": "text/html", "value": "<p>A party who controls what the application's <code>proxy_auth_fun</code> returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy.</p>", "base64": false}, {"type": "text/markdown", "value": "A party who controls what the application's `proxy_auth_fun` returns, for instance through the challenge headers of a proxy it can influence, can add header lines to the CONNECT request the client sends to its proxy.", "base64": false}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 2.1, "Automatable": "NOT_DEFINED", "attackVector": "LOCAL", "baseSeverity": "LOW", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "LOW", "vulnIntegrityImpact": "LOW", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "modules": ["hackney_http_connect"], "product": "hackney", "versions": [{"status": "affected", "version": "2.0.0", "lessThan": "4.9.0", "versionType": "semver"}], "packageURL": "pkg:hex/hackney", "packageName": "hackney", "programFiles": ["src/hackney_http_connect.erl"], "collectionURL": "https://repo.hex.pm", "defaultStatus": "unaffected", "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}]}, {"cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "modules": ["hackney_http_connect"], "product": "hackney", "versions": [{"status": "affected", "version": "5df5a74a2817d5b12880d217db33253ff1fae1b5", "lessThan": "5ee7d7d19eba27e774667d472feb1e93a08af7f9", "versionType": "git"}], "packageURL": "pkg:github/benoitc/hackney", "packageName": "benoitc/hackney", "programFiles": ["src/hackney_http_connect.erl"], "collectionURL": "https://github.com", "defaultStatus": "unaffected", "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}]}], "datePublic": "2026-10-25T00:00:00.000Z", "references": [{"url": "https://github.com/benoitc/hackney/releases/tag/4.9.0", "name": "hackney 4.9.0 release notes", "tags": ["vendor-advisory", "related"]}, {"url": "https://cna.erlef.org/cves/CVE-2026-112880.html", "name": "EEF CNA record for CVE-2026-112880", "tags": ["related"]}, {"url": "https://osv.dev/vulnerability/EEF-CVE-2026-112880", "name": "OSV record EEF-CVE-2026-112880", "tags": ["related"]}, {"url": "https://github.com/benoitc/hackney/pull/989", "name": "Refuse CR/LF/NUL in the proxy_auth_fun result (benoitc/hackney#989)", "tags": ["related"]}, {"url": "https://github.com/benoitc/hackney/commit/5df5a74a2817d5b12880d217db33253ff1fae1b5", "name": "Introducing commit 5df5a74 in benoitc/hackney", "tags": ["related"]}, {"url": "https://github.com/benoitc/hackney/commit/5ee7d7d19eba27e774667d472feb1e93a08af7f9", "name": "Fix commit 5ee7d7d in benoitc/hackney", "tags": ["patch"]}], "workarounds": [{"lang": "en", "value": "Check the value your proxy_auth_fun is about to return for CR, LF and NUL bytes and return {error, Reason} instead when one is present. The callback runs in the application, so the check can be made there.", "supportingMedia": [{"type": "text/html", "value": "<p>Check the value your <code>proxy_auth_fun</code> is about to return for CR, LF and NUL bytes and return <code>{error, Reason}</code> instead when one is present. The callback runs in the application, so the check can be made there.</p>", "base64": false}, {"type": "text/markdown", "value": "Check the value your `proxy_auth_fun` is about to return for CR, LF and NUL bytes and return `{error, Reason}` instead when one is present. The callback runs in the application, so the check can be made there.", "base64": false}]}], "dateAssigned": "2026-10-26T10:18:44.000Z", "descriptions": [{"lang": "en", "value": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller's proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0.", "supportingMedia": [{"type": "text/html", "value": "<p>Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in <code>hackney_http_connect</code> in benoitc hackney allows HTTP Request Splitting via the value a <code>proxy_auth_fun</code> callback returns. After a 407 response from an HTTP CONNECT proxy, <code>hackney_http_connect:handle_proxy_auth/11</code> calls the caller's <code>proxy_auth_fun</code> with the status code and the response headers and writes the returned binary into the <code>Proxy-Authorization</code> line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.</p>\n<p>The value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.</p>\n<p>This issue affects hackney: from 2.0.0 before 4.9.0.</p>", "base64": false}, {"type": "text/markdown", "value": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in `hackney_http_connect` in benoitc hackney allows HTTP Request Splitting via the value a `proxy_auth_fun` callback returns. After a 407 response from an HTTP CONNECT proxy, `hackney_http_connect:handle_proxy_auth/11` calls the caller's `proxy_auth_fun` with the status code and the response headers and writes the returned binary into the `Proxy-Authorization` line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0.", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-113", "description": "CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')"}]}], "configurations": [{"lang": "en", "value": "The client connects through an HTTP CONNECT proxy with the proxy_auth_fun option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without proxy_auth_fun, or whose callback returns a fixed credential, are not affected.", "supportingMedia": [{"type": "text/html", "value": "<p>The client connects through an HTTP CONNECT proxy with the <code>proxy_auth_fun</code> option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without <code>proxy_auth_fun</code>, or whose callback returns a fixed credential, are not affected.</p>", "base64": false}, {"type": "text/markdown", "value": "The client connects through an HTTP CONNECT proxy with the `proxy_auth_fun` option set, and the callback builds its result from data an untrusted party can influence, such as the proxy's 407 challenge headers. Deployments without `proxy_auth_fun`, or whose callback returns a fixed credential, are not affected.", "base64": false}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.9.0", "versionStartIncluding": "2.0.0"}], "operator": "OR"}], "operator": "AND"}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-10-26T13:48:46.589Z"}, "x_technicalAnalysis": [{"lang": "en", "value": "1. Challenge. hackney_http_connect:do_handshake_with_auth/9 in src/hackney_http_connect.erl sends the CONNECT request to the proxy. When the proxy answers 407 and the proxy_auth_fun option is set, it hands the status code and the parsed response headers to hackney_http_connect:handle_proxy_auth/11.\n\n2. Callback result. handle_proxy_auth/11 calls the caller's proxy_auth_fun with those two values. On {ok, AuthHeader} it removes any existing Proxy-Authorization header and appends the binary <<\"Proxy-Authorization: \", AuthHeader/binary>> to the header list, then retries the handshake with it.\n\n3. Splitting. The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside AuthHeader therefore ends the Proxy-Authorization line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same has_ctl_bytes/1 check to it and returns {error, {proxy_auth_error, invalid_header}}.", "supportingMedia": [{"type": "text/html", "value": "<p><strong>1. Challenge.</strong> <code>hackney_http_connect:do_handshake_with_auth/9</code> in <code>src/hackney_http_connect.erl</code> sends the CONNECT request to the proxy. When the proxy answers 407 and the <code>proxy_auth_fun</code> option is set, it hands the status code and the parsed response headers to <code>hackney_http_connect:handle_proxy_auth/11</code>.</p>\n<p><strong>2. Callback result.</strong> <code>handle_proxy_auth/11</code> calls the caller's <code>proxy_auth_fun</code> with those two values. On <code>{ok, AuthHeader}</code> it removes any existing <code>Proxy-Authorization</code> header and appends the binary <code>&lt;&lt;\"Proxy-Authorization: \", AuthHeader/binary&gt;&gt;</code> to the header list, then retries the handshake with it.</p>\n<p><strong>3. Splitting.</strong> The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside <code>AuthHeader</code> therefore ends the <code>Proxy-Authorization</code> line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same <code>has_ctl_bytes/1</code> check to it and returns <code>{error, {proxy_auth_error, invalid_header}}</code>.</p>", "base64": false}, {"type": "text/markdown", "value": "**1. Challenge.** `hackney_http_connect:do_handshake_with_auth/9` in `src/hackney_http_connect.erl` sends the CONNECT request to the proxy. When the proxy answers 407 and the `proxy_auth_fun` option is set, it hands the status code and the parsed response headers to `hackney_http_connect:handle_proxy_auth/11`.\n\n**2. Callback result.** `handle_proxy_auth/11` calls the caller's `proxy_auth_fun` with those two values. On `{ok, AuthHeader}` it removes any existing `Proxy-Authorization` header and appends the binary `<<\"Proxy-Authorization: \", AuthHeader/binary>>` to the header list, then retries the handshake with it.\n\n**3. Splitting.** The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside `AuthHeader` therefore ends the `Proxy-Authorization` line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same `has_ctl_bytes/1` check to it and returns `{error, {proxy_auth_error, invalid_header}}`.", "base64": false}]}]}}, "cveMetadata": {"cveId": "CVE-2026-112880", "state": "PUBLISHED", "dateUpdated": "2026-10-26T15:35:50.632Z", "dateReserved": "2026-10-26T10:15:01.166Z", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "datePublished": "2026-10-26T13:48:46.589Z", "assignerShortName": "EEF"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_http_connect"], "packageName": "hackney", "packageURL": "pkg:hex/hackney", "product": "hackney", "programFiles": ["src/hackney_http_connect.erl"], "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "4.9.0", "status": "affected", "version": "2.0.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_http_connect"], "packageName": "benoitc/hackney", "packageURL": "pkg:github/benoitc/hackney", "product": "hackney", "programFiles": ["src/hackney_http_connect.erl"], "programRoutines": [{"name": "hackney_http_connect:connect/4"}, {"name": "hackney_http_connect:do_handshake_with_auth/9"}, {"name": "hackney_http_connect:handle_proxy_auth/11"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "5ee7d7d19eba27e774667d472feb1e93a08af7f9", "status": "affected", "version": "5df5a74a2817d5b12880d217db33253ff1fae1b5", "versionType": "git"}]}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller's proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0."}], "id": "CVE-2026-112880", "lastModified": "2026-10-26T16:59:16.113", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 2.1, "baseSeverity": "LOW", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-112880", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-26T15:00:47.038622Z", "version": "2.0.3"}}]}, "published": "2026-10-26T14:16:28.440", "references": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://cna.erlef.org/cves/CVE-2026-112880.html"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/commit/5df5a74a2817d5b12880d217db33253ff1fae1b5"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/commit/5ee7d7d19eba27e774667d472feb1e93a08af7f9"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/pull/989"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://osv.dev/vulnerability/EEF-CVE-2026-112880"}], "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-113"}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.0.0,4.9.0)"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "hackney", "source": "cna", "vendor": "benoitc"}, "product": "hackney", "vendor": "benoitc"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5df5a74a2817d5b12880d217db33253ff1fae1b5,5ee7d7d19eba27e774667d472feb1e93a08af7f9)"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "hackney", "source": "cna", "vendor": "benoitc"}, "product": "hackney", "vendor": "benoitc"}], "created": "2026-10-26T15:45:12.505347+00:00", "updated": "2026-10-26T16:00:18.058361+00:00", "vendors": ["benoitc", "benoitc$PRODUCT$hackney"]}