Out-of-bounds read in Wasmtime - CVE-2026-34941
Published: April 10, 2026
Vulnerability identifier: #VU125764
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-34941
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Bytecode Alliance
Affected software:
Wasmtime
Wasmtime
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in the component model UTF-16 to latin1+utf16 string transcoding logic when processing cross-component string passing with UTF-16 source and latin1+utf16 destination encodings. A remote user can supply a crafted WebAssembly component string to cause a denial of service.
In the default configuration, exploitation causes the host process to crash with SIGBUS or SIGSEGV.
How to mitigate CVE-2026-34941
Install security update from vendor's website.