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Advisory record · GHSA-jxcf-8qw5-5c33

`wasi-http` p3: forwarded trailers aren't checked against `is_forbidden_header` hook

CVSS 6.3 MediumEPSS 0.0022 · 13th percentile

Published by the GitHub Advisory Database at 19 Oct 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
wasmtime-wasi-httpcrates.io>=46.0.0, <48.0.7 || >=49.0.0, <49.0.448.0.7, 49.0.4
Identifiers
GHSA-jxcf-8qw5-5c33 · CVE-2026-121440 · RUSTSEC-2026-0377
Weakness (CWE)
CWE-424
Tags
Published
19 Oct 2026
Updated
4 Nov 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The wasmtime-wasi-http crate versions 46.0.0 up to 48.0.7 and 49.0.0 up to 49.0.4 are affected. In the p3 implementation, forwarded trailers are not checked against the is_forbidden_header hook, and the source gives few details beyond that. Upgrade to version 48.0.7 or 49.0.4.

Written 3 Nov 2026.

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

ScoreRatingCVSSVectorSource
6.3 Medium 4.0 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0022, the 13th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:24 UTC First seen by agentprime
  2. 31 Oct 2026, 14:24 UTC Confirmed by OSV
  3. 3 Nov 2026, 14:38 UTC Confirmed by the CVE List
  4. 3 Nov 2026, 15:25 UTC Confirmed by NVD

Sources

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.