What is CVE-2026-119139?

CVE-2026-119139 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Reachable Assertion. CVSS score: 4.8/10. Published 2026-10-29.

How severe is CVE-2026-119139?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Bytecodealliance Wasmtime

CVE-2026-119139

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a leftover assertion in component::Func::call that rejects guest exports using the async ABI option. An attacker who supplies a component with an async-lifted export can crash the host process when an embedder invokes that export through Func::call.

Published 2026-10-29 · last modified 2026-10-29.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Bytecodealliance Wasmtime

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m6w2-jwq2-cv2c (vendor-advisory)
www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.6-and-49.0.0-before-49… (third-party-advisory)

Frequently asked questions

What is CVE-2026-119139?: CVE-2026-119139 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Reachable Assertion. CVSS score: 4.8/10. Published 2026-10-29.
How severe is CVE-2026-119139?: Medium severity. CVSS v3 base score is 4.8 out of 10.