CVE-2026-115383

Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via Tag Imports

State: Published
Severity: 5.9 Medium
Published: Oct 22, 2026
Updated: Oct 22, 2026
Reserved: Oct 22, 2026

Description

Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper validation vulnerability that accepts components whose core modules import WebAssembly tags with a subtype of the original type. Malicious guests can mis-type exception object payloads to corrupt the GC heap, causing Wasmtime to panic when the exceptions proposal is enabled.

Scores

CVSS	Score	Vector	Source
4.0	5.9 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	4.8 Medium	CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H	VulnCheck

Weaknesses

CWE-1287 Improper Validation of Specified Type of Input

Affected Products

Product	Versions
wasmtimebytecodealliance	47.0.0 to before 48.0.4Affected 48.0.4Not affected 49.0.0 to before 49.0.2Affected 49.0.2Not affected

References

GitHub Security Advisory (GHSA-cfhf-m2cr-62wj)vendor-advisory
VulnCheck Advisory: Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via Tag Importsthird-party-advisory

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