CVE-2026-84894
Received Received - Intake

MoQSession FIN Handling Flaw in moxygen

Publication date: 2026-09-28

Last updated on: 2026-09-28

Assigner: Facebook, Inc.

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.

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Meta Information

Published
2026-09-28
Last Modified
2026-09-28
Generated
2026-09-28
AI Q&A
2026-09-28
EPSS Evaluated
N/A
NVD
CVE-2026-84894
EUVD
EUVD-2026-88433

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
facebookexperimental moxygen *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability exists in moxygen before commit 004123dd24c3. The issue is in MoQSession::dataStreamReadLoop, which continues using a stream read handle after reading a FIN (Finish) signal. This invalidates the handle under proxygen's WebTransport API. A remote peer can exploit this by opening a data stream with an unknown track alias and sending the FIN in the same write operation.

Impact Analysis

A remote attacker could potentially disrupt or crash the affected service by triggering the stale handle usage. This may lead to denial-of-service conditions or unexpected behavior in applications using the moxygen library.

Mitigation Strategies

Update moxygen to the latest commit 004123dd24c3 or later to address the stale stream handle issue in MoQSession::dataStreamReadLoop.

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