CVE-2026-84894: Use After Free (CWE-416) in Meta Platforms, Inc moxygen
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.
AI Analysis
Technical Summary
This vulnerability involves a use-after-free condition (CWE-416) in the moxygen component of Meta Platforms, Inc. Specifically, the MoQSession::dataStreamReadLoop function improperly uses a stream read handle after it has been invalidated by receiving a FIN signal. The invalidation occurs due to the behavior of proxygen's WebTransport API. An attacker controlling a remote peer can exploit this by opening a data stream that references an unknown track alias and includes the FIN flag in the same write operation, causing the stale handle use.
Potential Impact
The use-after-free condition could potentially lead to undefined behavior such as application crashes or memory corruption. However, no known exploits in the wild have been reported. The exact impact beyond potential instability or denial of service is not detailed in the available information.
Mitigation Recommendations
No patch or official fix information is provided. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, cautious handling of untrusted data streams and monitoring for unusual application behavior may be advisable.
CVE-2026-84894: Use After Free (CWE-416) in Meta Platforms, Inc moxygen
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.
Affected software
Meta Platforms, Inc
moxygen
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a use-after-free condition (CWE-416) in the moxygen component of Meta Platforms, Inc. Specifically, the MoQSession::dataStreamReadLoop function improperly uses a stream read handle after it has been invalidated by receiving a FIN signal. The invalidation occurs due to the behavior of proxygen's WebTransport API. An attacker controlling a remote peer can exploit this by opening a data stream that references an unknown track alias and includes the FIN flag in the same write operation, causing the stale handle use.
Potential Impact
The use-after-free condition could potentially lead to undefined behavior such as application crashes or memory corruption. However, no known exploits in the wild have been reported. The exact impact beyond potential instability or denial of service is not detailed in the available information.
Mitigation Recommendations
No patch or official fix information is provided. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, cautious handling of untrusted data streams and monitoring for unusual application behavior may be advisable.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Meta
- Date Reserved
- 2026-09-02T14:52:36.354Z
- State
- PUBLISHED
Threat ID: 6abab9fff7a7c54106139f0d
Added to database: 09/28/2026, 19:03:27 UTC
Last enriched: 09/28/2026, 19:18:13 UTC
Last updated: 09/29/2026, 01:57:22 UTC
Views: 9
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