RUSTSEC-2026-0357: Out-of-bounds zero-length stream writes can panic

What to do

1. See which version you have: cargo tree -i wasmtime (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p wasmtime. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example wasmtime = "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-93g3-36p8-x2gc For more information see the GitHub-hosted security advisory.

References

• Package: crates.io/crates/wasmtime
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0357.html
• Web: github.com/bytecodealliance/wasmtime/pull/14740

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

• Vulnerability MediumRUSTSEC-2021-0110 · 2021-09-17Multiple Vulnerabilities in Wasmtime
• VulnerabilityRUSTSEC-2022-0016 · 2022-03-31Use after free with `externref`s and epoch interruption in Wasmtime
• VulnerabilityRUSTSEC-2022-0075 · 2022-11-10Bug in pooling instance allocator
• Vulnerability HighRUSTSEC-2022-0076 · 2022-11-10Bug in Wasmtime implementation of pooling instance allocator
• VulnerabilityRUSTSEC-2022-0095 · 2022-06-27Miscompilation of `i8x16.swizzle` and `select` with v128 inputs
• VulnerabilityRUSTSEC-2022-0096 · 2022-02-17Invalid drop of VMExternRef from partially-initialized instances in the pooling instance allocator
• Vulnerability LowRUSTSEC-2022-0097 · 2022-11-07Out of bounds write in `wasmtime_trap_code` C API function
• Vulnerability HighRUSTSEC-2022-0098 · 2022-11-05Data leakage between instances in the pooling allocator

Full security history of wasmtime