CVE-2026-6322High· 7.5▾ Twilightfast-uri normalize() decoded percent-encoded authority delimiters inside the host component and then re-emitted them as raw delimiters during serialization. A host that combined an allowed domain, an encoded at-sign, and a different doma…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Jul 4.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.5%
Last analysed / modified upstream
0.5% → 0.5%
fast-uri normalize() decoded percent-encoded authority delimiters inside the host component and then re-emitted them as raw delimiters during serialization. A host that combined an allowed domain, an encoded at-sign, and a different domain was re-emitted with the at-sign as a raw userinfo separator, changing the URI's authority to the second domain. Applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the input appeared to specify. Versions <= 3.1.1 are affected. Update to 3.1.2 or later.
fast-uri < 3.1.2Upgrade past the affected range:
fast-uri 3.1.2Connected by shared product, vendor, weakness, or advisory.
CVE-2026-13676High· 7.5fast-uri versions 2.3.1 through 3.1.2 and 4.0.0 fail to canonicalize Unicode (IDN) hostnames for HTTP-family URLs
CVE-2026-6321High· 7.5fast-uri decoded percent-encoded path separators and dot segments before applying dot-segment removal in its normalize() and equal() functions
CVE-2026-86818Medium· 4.8fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv, that added a mailto scheme parser in version 4.1.3
CVE-2026-86472Medium· 4.8fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv
CVE-2026-75899High· 7.5fast-uri: fast-uri: Server-Side Request Forgery via repeated hostname percent-decoding (CVE-2026-75899)
CVE-2026-75931High· 7.5fast-uri: fast-uri: Host confusion via skipped IDN canonicalization (CVE-2026-75931)