Integer overflow in Wasmtime - #VU155839
Published: October 15, 2026
Vulnerability identifier: #VU155839
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-190
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer overflow in the http crate used by wasmtime-wasi-http when processing guest-supplied request URLs. A remote attacker can use the WASI HTTP set-path-with-query operation to supply a URL with a query delimiter occurring after byte 65535 to cause a denial of service.
Exploitation requires the wrapped delimiter index to fall on an invalid character boundary.
Affected software
Wasmtime
Remediation
Install security update from vendor's website.
Wasmtime - addressed in versions 48.0.6, 49.0.3