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CVE-2026-24116 - Wasmtime segfault or unused out-of-sandbox load with f64.copysign operator on x86-64

CVE ID : CVE-2026-24116
Published : Jan. 27, 2026, 7:16 p.m. | 2 hours, 43 minutes ago
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.
Severity: 4.1 | MEDIUM
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Kenya Education Network CERT(KENET-CERT) is a Cybersecurity Emergency Response Team and Co-ordination Center operated by the National Research and Education Network of Kenya. KENET-CERT coordination center promotes awareness on cybersecurity incidences as well as coordinates and assists member institutions in responding effectively to cyber security threats and incidences. KENET-CERT works closely with Kenya's National CIRT coordination center (CIRT/CC) as a sector CIRT for the academic institutions. KENET promotes use of ICT in Teaching, Learning and Research in Higher Education Institutions in Kenya. KENET aims to interconnect all the Universities, Tertiary and Research Institutions in Kenya by setting up a cost effective and sustainable private network with high speed access to the global Internet. KENET also facilitates electronic communication among students and faculties in member institutions, share learning and teaching resources by collaboration in Research and Development of Educational content.