---
id: CVE-2026-84894
title: >-
  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
summary: >-
  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
  openin…
severity: none
cwe:
  - CWE-416
vendor: 'Meta Platforms, Inc'
product: moxygen
affected:
  - >-
    moxygen >= b24f8e65cb83ebe5f3880cc4e3a4c8f64e1882f9 <
    004123dd24c30dad6b649163575145f240dabc94
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T19:16:50.213'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84894'
references:
  - url: >-
      https://github.com/facebookexperimental/moxygen/commit/004123dd24c30dad6b649163575145f240dabc94
    label: cve-assign@fb.com
  - url: 'https://www.facebook.com/security/advisories/cve-2026-84894'
    label: cve-assign@fb.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-28T19:19:07.734Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.