CVE-2026-84894 – In moxygen before commit 004123dd24c3, MoQSession::dataStreamReadLoop keeps using a stream

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.