Bug 2565921 (CVE-2026-121439) - CVE-2026-121439 wasmtime: wasmtime: Response splitting via unvalidated Content-Length headers in wasi-http
Summary: CVE-2026-121439 wasmtime: wasmtime: Response splitting via unvalidated Conten...
Keywords:
Status: NEW
Alias: CVE-2026-121439
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-11-03 16:19 UTC by OSIDB Bzimport
Modified: 2026-11-03 16:51 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-11-03 16:19:19 UTC 
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.
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