fast-uri is a URI parser for Node.js. It canonicalizes a host to its ASCII form only when the input carries an explicit scheme, so a scheme-relative reference such as a host preceded by two slashes is returned with its host verbatim and no error set. As a result fast-uri's own entry points disagree with each other: parse, resolve, normalize, and equal can yield different hosts for the same input depending only on whether a scheme is written out, and equal can return opposite verdicts for the same pair of hosts. An application that extracts a host with fast-uri to check it against a policy list and then resolves the same reference can make its decision on one host while the destination is another, enabling host confusion and policy bypass. The affected versions are 2.4.2 up to but not including 2.4.5, 3.1.3 up to but not including 3.1.6, and 4.0.1 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which canonicalize the host consistently across the resolve path. Users should upgrade to a patched version.
Metrics
Affected Vendors & Products
References
History
Wed, 02 Sep 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Openjsf
Openjsf fast-uri |
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| CPEs | cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:* | |
| Vendors & Products |
Openjsf
Openjsf fast-uri |
Thu, 27 Aug 2026 18:00:00 +0000
| Type | Values Removed | Values Added |
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| Weaknesses | CWE-444 | |
| References |
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| Metrics |
threat_severity
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threat_severity
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Tue, 25 Aug 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Mon, 24 Aug 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Fast-uri
Fast-uri fast-uri |
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| Vendors & Products |
Fast-uri
Fast-uri fast-uri |
Mon, 24 Aug 2026 09:45:00 +0000
| Type | Values Removed | Values Added |
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| Description | fast-uri is a URI parser for Node.js. It canonicalizes a host to its ASCII form only when the input carries an explicit scheme, so a scheme-relative reference such as a host preceded by two slashes is returned with its host verbatim and no error set. As a result fast-uri's own entry points disagree with each other: parse, resolve, normalize, and equal can yield different hosts for the same input depending only on whether a scheme is written out, and equal can return opposite verdicts for the same pair of hosts. An application that extracts a host with fast-uri to check it against a policy list and then resolves the same reference can make its decision on one host while the destination is another, enabling host confusion and policy bypass. The affected versions are 2.4.2 up to but not including 2.4.5, 3.1.3 up to but not including 3.1.6, and 4.0.1 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which canonicalize the host consistently across the resolve path. Users should upgrade to a patched version. | |
| Title | fast-uri vulnerable to host confusion via skipped IDN canonicalization on scheme-relative references | |
| Weaknesses | CWE-436 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: openjs
Published: 2026-08-24T09:30:04.212Z
Updated: 2026-08-24T16:28:48.098Z
Reserved: 2026-08-18T15:43:33.460Z
Link: CVE-2026-75931
Updated: 2026-08-24T16:28:41.325Z
Status : Analyzed
Published: 2026-08-24T10:16:40.113
Modified: 2026-09-02T14:44:52.047
Link: CVE-2026-75931