fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding

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 0.0025, the 16th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 31 Oct 2026, 13:33 UTC First seen by agentprime
2. 31 Oct 2026, 13:33 UTC Confirmed by OSV

Sources

• GitHub Advisory Database: GHSA-w74x-v6f9-j3xg
• OSV: GHSA-w74x-v6f9-j3xg
• github.com/fastify/fast-uri/security/advisories/GHSA-w74x-v6f9-j3xg
• nvd.nist.gov/vuln/detail/CVE-2026-110306
• github.com/fastify/fast-uri/commit/39933a1f1422986f14e2d844f552238feb40f5d4
• github.com/fastify/fast-uri/commit/597f254c86d151568511eeb9a1df761fd12520b3
• github.com/fastify/fast-uri/commit/e60e716f41d1d73717e2d803d20b68d2c6d20a0f
• cna.openjsf.org/security-advisories.html
• github.com/fastify/fast-uri
• github.com/fastify/fast-uri/releases/tag/v2.4.8
• github.com/fastify/fast-uri/releases/tag/v3.1.9
• github.com/fastify/fast-uri/releases/tag/v4.2.3

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.