Reachable assertion in Wasmtime - #VU155841
Published: October 15, 2026
Vulnerability identifier: #VU155841
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-617
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 a reachable assertion in fused component adapters when transferring strings during same-instance component-to-component calls. A remote user can trigger a string transfer whose source and destination alias each other to cause a denial of service.
The issue can be triggered during normal default execution of a WebAssembly guest. User interaction is required.
Affected software
Wasmtime
Remediation
Install security update from vendor's website.
Wasmtime - update to 49.0.3