CVE-2026-84894

HIGH CVSS 3.1: 7.5 EPSS 0.26%
Updated Sep 30, 2026
Meta Platforms, Inc
Parameter Value
CVSS 7.5 (HIGH)
Type CWE-416 (Use After Free)
Vendor Meta Platforms, Inc
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products

meta platforms, inc:moxygen