CVE-2026-84894

Description

In moxygen before commit 004123dd24c3, MoQSession::dataStreamReadLoop keeps using a stream read handle after reading a FIN, which invalidates the handle under proxygen's WebTransport API. A remote peer can trigger the stale use by opening a data stream that names an unknown track alias and carries the FIN in the same write.

References

• https://github.com/facebookexperimental/moxygen/commit/004123dd24c30dad6b649163575145f240dabc94
• https://www.facebook.com/security/advisories/cve-2026-84894