PT-2026-31681 · Bytecode Alliance · Wasmtime

Published

2026-04-09

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Updated

2026-04-09

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CVE-2026-34942

CVSS v3.1

6.5

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Wasmtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1
Description Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings did not properly verify the alignment of reallocated strings. This could allow unaligned pointers to be passed to the host for transcoding, triggering a host panic. This panic can be triggered by malicious guests transferring specific strings across components with specific addresses. Host panics are considered a denial-of-service (DoS) vector as the panic conditions are controlled by the guest.
Recommendations Update to Wasmtime version 24.0.7 or later. Update to Wasmtime version 36.0.7 or later. Update to Wasmtime version 42.0.2 or later. Update to Wasmtime version 43.0.1 or later.

Fix

Buffer Overflow

Improper Validation of Array Index

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Weakness Enumeration

Related Identifiers

CVE-2026-34942
GHSA-JXHV-7H78-9775
RUSTSEC-2026-0092

Affected Products

Wasmtime