CVE-2026-34942
CVE-2026-34942 · Wasmtime panics when transcoding misaligned utf-16 strings
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 5.9 · Medium · EPSS 0.4% · Fix available
- Published
- Updated
Stack: system
Affected products and versions
wasmtime
- Versions
- < 24.0.7: Affected
- >= 25.0.0, < 36.0.7: Affected
- >= 37.0.0, < 42.0.2: Affected
- >= 43.0.0, < 44.0.1: Affected
No fix published
rust-wasmtime Debian:13
- Versions
- 26.0.1+dfsg-10
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 26.0.1+dfsg-5
- 26.0.1+dfsg-6
- 26.0.1+dfsg-7
- 26.0.1+dfsg-8
- 26.0.1+dfsg-9
- 27.0.0+dfsg-2
- 27.0.0+dfsg-3
- 27.0.0+dfsg-4
- 28.0.1+dfsg-1
- 28.0.1+dfsg-2
- 28.0.1+dfsg-3
- 29.0.1+dfsg-1
- 29.0.1+dfsg-2
- 29.0.1+dfsg-3
- 29.0.1+dfsg-4
- 29.0.1+dfsg-5
- 29.0.1+dfsg-6
- 29.0.1+dfsg-7
- 29.0.1+dfsg-8
- 36.0.11+dfsg-1
- 36.0.12+dfsg-1
- 36.0.12+dfsg-2
- 36.0.12+dfsg-3
- 36.0.13+dfsg-1
- 36.0.5+dfsg-1
- 36.0.5+dfsg-2
- 36.0.5+dfsg-3
- 36.0.5+dfsg-4
- 36.0.5+dfsg-5
- 36.0.6+dfsg-1
- 36.0.6+dfsg-2
- 36.0.6+dfsg-3
- 36.0.6+dfsg-4
- 36.0.6+dfsg-5
- 36.0.6+dfsg-6
- 36.0.6+dfsg-7
- 36.0.7+dfsg-1
- 36.0.8+dfsg-1
- 36.0.9+dfsg-1
- 36.0.9+dfsg-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Debian:14
- Versions
- 26.0.1+dfsg-10
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 26.0.1+dfsg-5
- 26.0.1+dfsg-6
- 26.0.1+dfsg-7
- 26.0.1+dfsg-8
- 26.0.1+dfsg-9
- 27.0.0+dfsg-2
- 27.0.0+dfsg-3
- 27.0.0+dfsg-4
- 28.0.1+dfsg-1
- 28.0.1+dfsg-2
- 28.0.1+dfsg-3
- 29.0.1+dfsg-1
- 29.0.1+dfsg-2
- 29.0.1+dfsg-3
- 29.0.1+dfsg-4
- 29.0.1+dfsg-5
- 29.0.1+dfsg-6
- 29.0.1+dfsg-7
- 29.0.1+dfsg-8
- 36.0.5+dfsg-1
- 36.0.5+dfsg-2
- 36.0.5+dfsg-3
- 36.0.5+dfsg-4
- 36.0.5+dfsg-5
- 36.0.6+dfsg-1
- 36.0.6+dfsg-2
- 36.0.6+dfsg-3
- 36.0.6+dfsg-4
- 36.0.6+dfsg-5
- 36.0.6+dfsg-6
- 36.0.6+dfsg-7
- Affected ranges
- ECOSYSTEM: < 36.0.7+dfsg-1
Update to 36.0.7+dfsg-1
rust-wasmtime Ubuntu:24.04:LTS
- Versions
- 10.0.1+dfsg-7
- 15.0.1+dfsg-4
- 16.0.0+dfsg-2
- 16.0.0+dfsg-3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:25.10
- Versions
- 26.0.1+dfsg-3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:26.10
- Versions
- 36.0.5+dfsg-1
- 36.0.13+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:26.04:LTS
- Versions
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 28.0.1+dfsg-3
- 29.0.1+dfsg-5
- 36.0.5+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published