Improper Enforcement of Behavioral Workflow in Wasmtime - #VU155845
Published: October 15, 2026
Vulnerability identifier: #VU155845
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-841
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to insufficient enforcement of async-entrypoint requirements in the Wasmtime store when host functions re-enter WebAssembly through synchronous APIs during an asynchronous call and the store does not otherwise require asynchronous entrypoints. A remote user can trigger affected embedder execution paths to cause a denial of service through runtime panics in certain scheduling situations.
The issue cannot be controlled by guest code. Stack-resident non-Send values, such as Rc<T>, can additionally make suspension and movement of host code across threads unsound.
Affected software
Wasmtime
Remediation
Install security update from vendor's website.
Wasmtime - addressed in versions 48.0.6, 49.0.3