What is CVE-2026-34943?

CVE-2026-34943 is a high-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-248. CVSS score: 7.5/10. Published 2026-04-09.

How severe is CVE-2026-34943?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Bytecodealliance Wasmtime

CVE-2026-34943

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the se…

EPSS: 0.003 (24.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Bytecodealliance Wasmtime — versions < 24.0.7, >= 25.0.0, < 36.0.7, >= 37.0.0, < 42.0.2

Weakness classification (CWE)

CWE-248

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-34943?: CVE-2026-34943 is a high-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-248. CVSS score: 7.5/10. Published 2026-04-09.
How severe is CVE-2026-34943?: High severity. CVSS v3 base score is 7.5 out of 10.