CVE-2026-34946

Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a vulnerability where the compilation of the table.fill instruction can result in a host panic. This means that a valid guest can be compiled with Winch, on any architecture, and cause the host to panic. This represents a denial-of-service vulnerability in Wasmtime due to guests being able to trigger a panic. The specific issue is that a historical refactoring changed how compiled code referenced tables within the table.* instructions. This refactoring forgot to update the Winch code paths associated as well, meaning that Winch was using the wrong indexing scheme. Due to the feature support of Winch the only problem that can result is tables being mixed up or nonexistent tables being used, meaning that the guest is limited to panicking the host (using a nonexistent table), or executing spec-incorrect behavior and modifying the wrong table. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.

CVSS

No CVSS.

References

Link	Resource
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q49f-xg75-m9xw

Configurations

No configuration.

History

09 Apr 2026, 19:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-09 19:16

Updated : 2026-04-09 19:16

NVD link : CVE-2026-34946

Mitre link : CVE-2026-34946

CVE.ORG link : CVE-2026-34946

JSON object : View

Products Affected

No product.

CWE

CWE-670

Always-Incorrect Control Flow Implementation

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