CVE-2026-84895 Use after free in proxygen
Use-after-free in proxygen's QuicWtSession allows attackers to cause crashes or potentially execute code via session closure.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-84895?
CVE-2026-84895 is a high-severity use after free vulnerability in Facebook proxygen, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2026-84895?
How do I fix CVE-2026-84895?
No fix has been published for CVE-2026-84895 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-84895 being exploited?
There is no known exploitation of CVE-2026-84895 in the wild and no public exploit code.
Sources
Also known as GHSA-ppxw-566f-wjp6.