Wasmtime has an out-of-bounds write or crash when transcoding component model strings
Summary
Wasmtime has an out-of-bounds write or crash when transcoding component model 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 between components contains a bug where the return value of a guest component's realloc is not validated before the host attempts to write through the pointer. This enables a guest to cause the host to write arbitrary transcoded string bytes to an arbitrary location up to 4GiB away from the base of linear memory. These writes on the host could hit unmapped memory or could corrupt host data structures depending on Wasmtime's configuration. Wasmtime by default reserves 4GiB of virtual memory for a guest's linear memory meaning that this bug will by default on hosts cause the host to hit unmapped memory and abort the process due to an unhandled fault. Wasmtime can be configured, however, to reserve less memory for a guest and to remove all guard pages, so some configurations of Wasmtime may lead to corruption of data outside of a guest's linear memory, such as host data structures or other guests's linear memories. 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-2026-35195 rust-wasmtime
- Ubuntu UBUNTU-CVE-2026-35195 rust-wasmtime
References
- advisory rustsec.org
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package crates.io
- web github.com