wasmtime_trap_code C API function has out of bounds write vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.8 · CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L

EPSS

• CVE-2022-39394: 0.35% estimated exploitation activity in the next 30 days; percentile 29.20 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact There is a bug in Wasmtime's C API implementation where the definition of the wasmtimetrapcode does not match its declared signature in the wasmtime/trap.h header file. This discrepancy causes the function implementation to perform a 4-byte write into a 1-byte buffer provided by the caller. This can lead to three zero bytes being written beyond the 1-byte location provided by the caller. Patches This bug has been patched and users should upgrade to Wasmtime 2.0.2. Workarounds This can be worked around by providing a 4-byte buffer casted to a 1-byte buffer when calling wasmtimetrapcode. Users of the wasmtime crate are not affected by this issue, only users of the C API function wasmtimetrapcode are affected. References Definition of wasmtimetrapcode Mailing list announcement Patch to fix for main branch For more information If you have any questions or comments about this advisory: Reach out to us on the Bytecode Alliance Zulip chat Open an issue in the…

Published by the source

1 Feb 2024, 00:15 UTC

Last modified by the source

2 May 2025, 12:51 UTC

Source last checked

26 Oct 2026, 15:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h84q-m8rr-3v9q

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# Patch Next advisory brief: CVE-2022-39394

Advisory: wasmtime_trap_code C API function has out of bounds write vulnerability
IDs: CVE-2022-39394, GHSA-h84q-m8rr-3v9q
Record: https://patchnext.com/advisories/cve-2022-39394 (revision 1, source checked 26 Oct 2026, 15:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: wasmtime 2.0.2, 1.0.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io wasmtime: affected >= 2.0.0, < 2.0.2; < 1.0.2; fixed in 1.0.2, 2.0.2

## Suggested inspection (read-only)
- crates.io wasmtime: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wasmtime.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h84q-m8rr-3v9q (GitHub-reviewed advisory GHSA-h84q-m8rr-3v9q lists affected ranges: crates.io wasmtime >=2.0.0 =0 <1.0.2)

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