Wasmtime panics when transcoding misaligned utf-16 strings
Summary
Wasmtime panics when transcoding misaligned utf-16 strings
Original description
The description as published by the source.
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.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-34942 rust-wasmtime
- Ubuntu UBUNTU-CVE-2026-34942 rust-wasmtime
References
- advisory rustsec.org
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package crates.io
- web github.com