[ CVE-2026-121439 · Published 3 Nov 2026 ]
Vulnerability in bytecodealliance wasmtime
CVSS 5.3
EPSS <1%No fix listed yet
[ Description ]Official description
Wasmtime 46.0.0 before 48.0.7 and 49.0.0 before 49.0.4 contains a response splitting vulnerability in wasi-http p3 that allows guests to set unvalidated content-length headers. Malicious wasip3 guests can splice an existing body into a new response with an incorrect content-length to perform response splitting or injection attacks.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.