CVE-2026-84394

NameCVE-2026-84394
Descriptionfast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error. A host that starts with an opening bracket but does not end with a closing bracket is neither validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its policy against a string that is not the host the request reaches. The same host is carried through normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in 2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but is not a valid IPv6 literal.
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 Bugs1146660

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
forky8.20.0~ds+~cs7.1.3-3vulnerable
sid8.20.0~ds+~cs7.1.5-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
node-ajvsourcebookworm(not affected)
node-ajvsource(unstable)8.20.0~ds+~cs7.1.5-11146660

Notes

[trixie] - node-ajv <no-dsa> (Minor issue)
[bookworm] - node-ajv <not-affected> (fast-uri not present)
https://github.com/fastify/fast-uri/security/advisories/GHSA-58mr-gqgx-xq4g
Embedded fast-uri used and provided as node-fast-uri, starting with forky

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