{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-121440", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-11-03T12:32:14.752Z", "datePublished": "2026-11-03T14:28:31.228Z", "dateUpdated": "2026-11-03T14:28:31.228Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-11-03T14:28:31.228Z"}, "datePublic": "2026-10-19T00:00:00.000Z", "title": "Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 Forwarded Trailers Header Filter Bypass", "descriptions": [{"lang": "en", "value": "Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 fails to check forwarded trailers against the WasiHttpHooks::is_forbidden_header hook in wasi-http p3. WASIp3 guests can forward a request or response body so its trailers skip embedder-customized forbidden header filtering, undermining header restrictions the embedder intended."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Improper Protection of Alternate Path", "cweId": "CWE-424", "type": "CWE"}]}], "affected": [{"vendor": "bytecodealliance", "product": "wasmtime", "defaultStatus": "unaffected", "packageURL": "pkg:cargo/wasmtime-wasi-http", "versions": [{"version": "46.0.0", "status": "affected", "versionType": "semver", "lessThan": "48.0.7"}, {"version": "48.0.7", "status": "unaffected", "versionType": "semver"}, {"version": "49.0.0", "status": "affected", "versionType": "semver", "lessThan": "49.0.4"}, {"version": "49.0.4", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*", "versionStartIncluding": "46.0.0", "versionEndExcluding": "48.0.7"}, {"vulnerable": true, "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*", "versionStartIncluding": "49.0.0", "versionEndExcluding": "49.0.4"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 6.3, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE", "baseScore": 3.7, "baseSeverity": "LOW"}}], "references": [{"url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxcf-8qw5-5c33", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-jxcf-8qw5-5c33)"}, {"name": "VulnCheck Advisory: Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 Forwarded Trailers Header Filter Bypass", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.7-and-49.0.0-before-49.0.4-forwarded-trailers-header-filter-bypass"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:cargo/wasmtime-wasi-http", "product": "wasmtime", "vendor": "bytecodealliance", "versions": [{"lessThan": "48.0.7", "status": "affected", "version": "46.0.0", "versionType": "semver"}, {"status": "unaffected", "version": "48.0.7", "versionType": "semver"}, {"lessThan": "49.0.4", "status": "affected", "version": "49.0.0", "versionType": "semver"}, {"status": "unaffected", "version": "49.0.4", "versionType": "semver"}]}], "source": "[email protected]"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 fails to check forwarded trailers against the WasiHttpHooks::is_forbidden_header hook in wasi-http p3. WASIp3 guests can forward a request or response body so its trailers skip embedder-customized forbidden header filtering, undermining header restrictions the embedder intended."}], "id": "CVE-2026-121440", "lastModified": "2026-11-03T15:17:35.863", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.7, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "[email protected]", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "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": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/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": "[email protected]", "type": "Secondary"}]}, "published": "2026-11-03T15:17:35.707", "references": [{"source": "[email protected]", "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxcf-8qw5-5c33"}, {"source": "[email protected]", "url": "https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.7-and-49.0.0-before-49.0.4-forwarded-trailers-header-filter-bypass"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-424"}], "source": "[email protected]", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[46.0.0,48.0.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "48.0.7"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[49.0.0,49.0.4)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "49.0.4"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "wasmtime", "source": "cna", "vendor": "bytecodealliance"}, "product": "wasmtime", "vendor": "bytecodealliance"}], "created": "2026-11-03T16:00:17.526579+00:00", "updated": "2026-11-03T17:00:16.643237+00:00", "vendors": ["bytecodealliance", "bytecodealliance$PRODUCT$wasmtime"]}