CVE-2026-119133

Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Misaligned VMContext via Exception Tags

State: Published
Severity: 2.1 Low
Published: Oct 29, 2026
Updated: Oct 29, 2026
Reserved: Oct 29, 2026

Description

Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.

Scores

CVSS	Score	Vector	Source
4.0	2.1 Low	CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N	VulnCheck
3.1	2.6 Low	CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N	VulnCheck

Weaknesses

CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

Affected Products

Product	Versions
wasmtimebytecodealliance	47.0.0 to before 48.0.6Affected 48.0.6Not affected 49.0.0 to before 49.0.3Affected 49.0.3Not affected

References

GitHub Security Advisory (GHSA-p79w-pv2r-29qp)vendor-advisory
VulnCheck Advisory: Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Misaligned VMContext via Exception Tagsthird-party-advisory

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