CVE-2026-84895: Use After Free (CWE-416) in Facebook proxygen
In proxygen from v2026.04.06.00 until v2026.09.28.00, QuicWtSession::closeSession accesses its member fields after calling the base QuicWtSessionBase::closeSession method. The base method notifies the session handler, which may release the last reference to the session and destroy it.
AI Analysis
Technical Summary
The vulnerability exists in proxygen's QuicWtSession component where the closeSession method accesses member fields after invoking the base class closeSession method. The base method notifies the session handler, potentially releasing the last reference to the session and destroying it. Subsequent access to the destroyed session's members results in a use-after-free condition (CWE-416). This affects versions >=2026.04.06.00 and <2026.09.28.00.
Potential Impact
Exploitation of this use-after-free vulnerability could lead to undefined behavior including potential crashes or memory corruption within applications using the affected proxygen versions. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor for vendor updates and apply any official fixes once available.
CVE-2026-84895: Use After Free (CWE-416) in Facebook proxygen
Description
In proxygen from v2026.04.06.00 until v2026.09.28.00, QuicWtSession::closeSession accesses its member fields after calling the base QuicWtSessionBase::closeSession method. The base method notifies the session handler, which may release the last reference to the session and destroy it.
Affected software
proxygen
pkg:github/facebook/proxygenRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in proxygen's QuicWtSession component where the closeSession method accesses member fields after invoking the base class closeSession method. The base method notifies the session handler, potentially releasing the last reference to the session and destroying it. Subsequent access to the destroyed session's members results in a use-after-free condition (CWE-416). This affects versions >=2026.04.06.00 and <2026.09.28.00.
Potential Impact
Exploitation of this use-after-free vulnerability could lead to undefined behavior including potential crashes or memory corruption within applications using the affected proxygen versions. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor for vendor updates and apply any official fixes once available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Meta
- Date Reserved
- 2026-09-02T14:52:36.354Z
- State
- PUBLISHED
Threat ID: 6abad292f7a7c541062fe5b5
Added to database: 09/28/2026, 20:48:18 UTC
Last enriched: 09/28/2026, 21:03:15 UTC
Last updated: 09/29/2026, 02:52:24 UTC
Views: 9
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