CVE-2026-75931

NameCVE-2026-75931
Descriptionfast-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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1145882

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
node-ajv (PTS)bookworm6.12.6-3fixed
trixie8.12.0~ds+~2.1.1-5vulnerable
forky, sid8.20.0~ds+~cs7.1.5-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
node-ajvsourcebullseye(not affected)
node-ajvsourcebookworm(not affected)
node-ajvsource(unstable)8.20.0~ds+~cs7.1.4-11145882

Notes

[trixie] - node-ajv <no-dsa> (Minor issue)
[bookworm] - node-ajv <not-affected> (fast-uri not present)
[bullseye] - node-ajv <not-affected> (fast-uri not present)
https://github.com/fastify/fast-uri/security/advisories/GHSA-5jgf-p345-68v8
Embedded fast-uri used and provided as node-fast-uri, starting with forky

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