RUSTSEC-2026-0351: `wasi-http`: Request with long url before query parameter crashes host

What to do

1. See which version you have: cargo tree -i wasmtime-wasi-http (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p wasmtime-wasi-http. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example wasmtime-wasi-http = "49.0.3") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-w36r-2hch-9xp9 For more information see the GitHub-hosted security advisory.

References

• Package: crates.io/crates/wasmtime-wasi-http
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0351.html
• Web: github.com/bytecodealliance/wasmtime/pull/14728

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for wasmtime-wasi-http

• Vulnerability MediumRUSTSEC-2026-0313 · 2026-09-24Outgoing HTTP body write allows guest-driven host memory exhaustion
• VulnerabilityRUSTSEC-2026-0320 · 2026-10-02Wasmtime wasi:http implementation panics with a zero timeout supplied
• VulnerabilityRUSTSEC-2026-0350 · 2026-10-14Guests can send absolute-form HTTP requests to different hosts
• Vulnerability MediumRUSTSEC-2026-0375 · 2026-10-19`wasi-http` p3: Guests can set incorrect content-length for spliced response bodies
• Vulnerability LowRUSTSEC-2026-0376 · 2026-10-19`wasi-http`: Guests can add conflicting content lengths to messages
• Vulnerability LowRUSTSEC-2026-0377 · 2026-10-19`wasi-http` p3: forwarded trailers aren't checked against `is_forbidden_header` hook

Full security history of wasmtime-wasi-http