High severity · published Sep 28, 2026
CVE-2026-84894
In moxygen before commit 004123dd24c3, MoQSession::dataStreamReadLoop keeps using a stream read handle after reading a FIN, which invalidates the handle under proxygen's…
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 17% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
moxygen · Meta Platforms, Inc
b24f8e65cb83ebe5f3880cc4e3a4c8f64e1882f9 before 004123dd24c30dad6b649163575145f240dabc94 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-84894
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-84894
x_refsource_CONFIRM
https://www.facebook.com/security/advisories/cve-2026-84894
x_refsource_MISC
https://github.com/facebookexperimental/moxygen/commit/004123dd24c30dad6b649163575145f240dabc94