CVE-2026-24116
MEDIUM
GHSA-vc8c-j3xm-xj73
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Lifecycle Timeline
3Description
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.
Analysis
Wasmtime versions 29.0.0 through 41.0.0 on x86-64 platforms with AVX contain an out-of-bounds memory read in the f64.copysign instruction compilation that can cause application crashes when signal-based traps are disabled. In configurations with disabled guard pages, this vulnerability could potentially leak out-of-sandbox data, though the data remains inaccessible to WebAssembly guests without additional Cranelift bugs. …
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Remediation
Within 30 days: Identify affected systems running version 29.0.0 and and apply vendor patches as part of regular patch cycle. Vendor patch is available.
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External POC / Exploit Code
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