CVE-2026-34942
Description
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be passed to the host for transcoding which would trigger a host panic. This panic is possible to trigger from malicious guests which transfer very specific strings across components with specific addresses. Host panics are considered a DoS vector in Wasmtime as the panic conditions are controlled by the guest in this situation. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | forky | fixed | 36.0.7+dfsg-1 |
| debian | sid | fixed | 36.0.7+dfsg-1 |
| debian | trixie | affected | |
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxhv-7h78-9775
- https://www.suse.com/security/cve/CVE-2026-34942.html
- https://nvd.nist.gov/vuln/detail/CVE-2026-34942
- https://github.com/bytecodealliance/wasmtime
- https://rustsec.org/advisories/RUSTSEC-2026-0092.html
- https://crates.io/crates/wasmtime
- https://security-tracker.debian.org/tracker/CVE-2026-34942
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.