CVE-2026-63946 Bluetooth: ISO: fix UAF in iso_recv_frame
A use-after-free in the Linux kernel Bluetooth ISO subsystem allows attackers to execute arbitrary code or escalate privileges via crafted frames.
- 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-2026-63946?
CVE-2026-63946 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 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: ISO: fix UAF in iso_recv_frame
iso_recv_frame reads conn->sk under iso_conn_lock but releases the lock before using sk, with no reference held. A concurrent iso_sock_kill() can free sk in that window, causing use-after-free on sk->sk_state and sock_queue_rcv_skb().
Fix by replacing the bare pointer read with iso_sock_hold(conn), which calls sock_hold() while the spinlock is held, atomically elevating the refcount before the lock drops. Add a drop_put label so sock_put() is called on all exit paths where the hold succeeded.
Which versions are affected by CVE-2026-63946?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63946?
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-2026-63946 being exploited?
There is no known exploitation of CVE-2026-63946 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63946, DEBIAN-CVE-2026-63946, GHSA-9g79-vcq4-5rfr, UBUNTU-CVE-2026-63946.