VYPR
Moderate severityOSV Advisory· Published Jan 27, 2026· Updated Jan 27, 2026

Wasmtime segfault or unused out-of-sandbox load with f64.copysign operator on x86-64

CVE-2026-24116

Description

Wasmtime is a runtime for WebAssembly. Starting in version 29.0.0 and prior to version 36.0.5, 40.0.3, and 41.0.1, on x86-64 platforms with AVX, Wasmtime's compilation of the f64.copysign WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but unless there is another bug in Cranelift this data is not visible to WebAssembly guests. Wasmtime 36.0.5, 40.0.3, and 41.0.1 have been released to fix this issue. Users are recommended to upgrade to the patched versions of Wasmtime. Other affected versions are not patched and users should updated to supported major version instead. This bug can be worked around by enabling signals-based-traps. While disabling guard pages can be a quick fix in some situations, it's not recommended to disabled guard pages as it is a key defense-in-depth measure of Wasmtime.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
wasmtimecrates.io
>= 29.0.0, < 36.0.536.0.5
wasmtimecrates.io
>= 37.0.0, < 40.0.340.0.3
wasmtimecrates.io
>= 41.0.0, < 41.0.141.0.1

Affected products

10

Patches

Vulnerability mechanics

References

10

News mentions

0

No linked articles in our index yet.