fast-uri vulnerable to host confusion via percent-encoded scheme normalization

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0023, the 14th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 2 Sept 2026. New records show when each source confirmed them.

Sources

• GitHub Advisory Database: GHSA-jqff-g426-hqxp
• OSV: GHSA-jqff-g426-hqxp
• github.com/fastify/fast-uri/security/advisories/GHSA-jqff-g426-hqxp
• nvd.nist.gov/vuln/detail/CVE-2026-76172
• github.com/fastify/fast-uri/commit/37f3417c82994279656854f83ce938acd81c3862
• github.com/fastify/fast-uri/commit/a941e626411f576f8d90883231e57b6c9d0ff98b
• github.com/fastify/fast-uri/commit/c6a74bfd9d8c6b0df5362b3c7ae88d8021cb1e39
• cna.openjsf.org/security-advisories.html
• github.com/fastify/fast-uri
• github.com/fastify/fast-uri/releases/tag/v2.4.5
• github.com/fastify/fast-uri/releases/tag/v3.1.6
• github.com/fastify/fast-uri/releases/tag/v4.1.3

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.