fast-uri serializes the port component of a URI without validating it. When recomposing the authority, the userinfo and host components are escaped but the port is concatenated verbatim, so a port value that is not a sequence of digits can inject authority delimiters, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both fast-uri and Node's URL read the result back as the attacker's host with no error, so re-validating the built URI does not catch it. This affects applications that build URIs from parts and assign untrusted data to the port component through the serialize, normalize, or equal functions in their object forms. The issue affects fast-uri versions before 2.4.6, from 3.0.0 before 3.1.7, and from 4.0.0 before 4.1.4. It is fixed in 2.4.6, 3.1.7, and 4.1.4, where recomposeAuthority rejects any port that is not a digit sequence per RFC 3986.
Advisories

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Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Thu, 03 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 03 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-140
References
Metrics threat_severity

None

threat_severity

Important


Thu, 03 Sep 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Fast-uri
Fast-uri fast-uri
Vendors & Products Fast-uri
Fast-uri fast-uri

Wed, 02 Sep 2026 20:15:00 +0000

Type Values Removed Values Added
Description fast-uri serializes the port component of a URI without validating it. When recomposing the authority, the userinfo and host components are escaped but the port is concatenated verbatim, so a port value that is not a sequence of digits can inject authority delimiters, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both fast-uri and Node's URL read the result back as the attacker's host with no error, so re-validating the built URI does not catch it. This affects applications that build URIs from parts and assign untrusted data to the port component through the serialize, normalize, or equal functions in their object forms. The issue affects fast-uri versions before 2.4.6, from 3.0.0 before 3.1.7, and from 4.0.0 before 4.1.4. It is fixed in 2.4.6, 3.1.7, and 4.1.4, where recomposeAuthority rejects any port that is not a digit sequence per RFC 3986.
Title fast-uri vulnerable to authority injection via an unvalidated port in serialize
Weaknesses CWE-116
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-09-03T13:16:25.237Z

Reserved: 2026-09-01T16:10:49.688Z

Link: CVE-2026-84292

cve-icon Vulnrichment

Updated: 2026-09-03T13:16:21.895Z

cve-icon NVD

Status : Received

Published: 2026-09-02T20:17:39.543

Modified: 2026-09-03T14:17:02.943

Link: CVE-2026-84292

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-02T20:09:51Z

Links: CVE-2026-84292 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-03T14:15:06Z

Weaknesses