PT-2026-31684 · Bytecode Alliance · Wasmtime

Published 2026-04-09 · Updated 2026-05-06 · CVE-2026-34943

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/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, a runtime for WebAssembly, may experience a panic when a flags-typed component model value is lifted with the Val type. This occurs if bits are set outside the expected flags, leading to a guest-controlled panic within the host, which is considered a denial-of-service vector. This issue specifically affects flags-typed values within a WIT interface and the lifting process into Val, not the flags! macro.

Recommendations Update to Wasmtime version 24.0.7, 36.0.7, 42.0.2, or 43.0.1.

Fix

Weakness Enumeration

CWE-248

Related Identifiers

CVE-2026-34943

GHSA-M758-WJHJ-P3JQ

OPENSUSE-SU-2026:10715-1

RUSTSEC-2026-0085

Affected Products

Wasmtime

References · 19

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq · Vendor Advisory
• https://osv.dev/vulnerability/RUSTSEC-2026-0085 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-34943 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-34943 · Security Note
• https://ubuntu.com/security/CVE-2026-34943 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-34943 · Security Note
• https://osv.dev/vulnerability/GHSA-m758-wjhj-p3jq · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-34943 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:10715-1 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-34943 · Vendor Advisory
• https://github.com/bytecodealliance/wasmtime · Note
• https://twitter.com/CVEnew/status/2042340089049526546 · Twitter Post
• https://suse.com/security/cve/CVE-2026-34988 · Note
• https://rustsec.org/advisories/RUSTSEC-2026-0085.html · Note
• https://suse.com/security/cve/CVE-2026-35186 · Note