Medium severity · published Oct 29, 2026
CVE-2026-119140
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Host Panic via thread.yield
New
4.8
CVSS
–
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
Required
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WA
wasmtime · bytecodealliance
46.0.0 before 48.0.6; 49.0.0 before 49.0.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-119140
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-119140
vendor-advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-5hhx-4wrr-3j9g
third-party-advisory
https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.6-and-49.0.0-before-49.0.3-host-panic-via-thread-yield
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