fastify vulnerable to X-Forwarded-* spoofing under trustProxy hop-count

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 0.0016, the 4th 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-3m5p-2c4r-xxw2
• OSV: GHSA-3m5p-2c4r-xxw2
• github.com/fastify/fastify/security/advisories/GHSA-3m5p-2c4r-xxw2
• nvd.nist.gov/vuln/detail/CVE-2026-16732
• github.com/fastify/fastify/commit/8acfea7eada05383a7357e3eb21c2628416df280
• cna.openjsf.org/security-advisories.html
• github.com/fastify/fastify
• github.com/fastify/fastify/releases/tag/v5.12.1

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.