CVE-2026-89774 Bluetooth: SCO: hold sk properly in sco_conn_ready
A race condition in the Linux kernel Bluetooth SCO subsystem allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89774?
CVE-2026-89774 is a high-severity use after free vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: SCO: hold sk properly in sco_conn_ready
sk deref in sco_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk and parent sk is currently accessed without either, and without checking parent->sk_state:
[Task 1] [Task 2] sco_sock_release sco_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) sco_sock_kill(sk) UAF on sk deref
and similarly for access to sco_get_sock_listen() return value.
Fix possible UAF by holding sk refcount in sco_conn_ready() and making sco_get_sock_listen() increase refcount. Also recheck after lock_sock that the socket is still valid. Adjust conn->sk locking so it's protected also by lock_sock() of the associated socket if any.
Which versions are affected by CVE-2026-89774?
How do I fix CVE-2026-89774?
Apply the vendor's patch.
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-2026-89774 being exploited?
There is no known exploitation of CVE-2026-89774 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89774, DEBIAN-CVE-2026-89774, GHSA-g3p6-8r9x-w9g7, UBUNTU-CVE-2026-89774.