CVE-2026-121441

Low CVSS 3.7

Published 2026-11-03 · last changed 2026-11-03

The fix

We hold no Microsoft remediation data for CVE-2026-121441, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send HTTP requests with conflicting content-length values to smuggle requests through servers or intermediaries that do not reject them.

Sources

NVD record for CVE-2026-121441

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N