Vulnerability in Bytecodealliance Wasmtime
CVE-2026-119140
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows malicious components to panic the host via thread.yield in start functions. Attackers can supply a component whose start function calls an async-lowered import then thread.yield, causing an undisposed fiber drop that crashes embedders.
Published · last modified .
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
Weakness classification (CWE)
References
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-5hhx-4wrr-3j9g (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-2026-119140?
- CVE-2026-119140 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-372. CVSS score: 4.8/10. Published 2026-10-29.
- How severe is CVE-2026-119140?
- Medium severity. CVSS v3 base score is 4.8 out of 10.