CVE-2026-63946

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.

Weakness

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Software

Extended Description

A race condition occurs within concurrent environments, and it is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:

A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the product; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable product.

Potential Mitigations

• Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring.
• Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://git.kernel.org/stable/c/119fb6f80c44dc1c65d604cf28e64c56bd9b6568
• https://git.kernel.org/stable/c/1a6b803b00ccdd7666506adbe01ddae1c72d1ca9
• https://git.kernel.org/stable/c/47f23a259517abbdb8032c057a1e8a6bf3734878
• https://git.kernel.org/stable/c/b04ec131325baf4ea4577d6c6e6b86cf092e3731
• https://git.kernel.org/stable/c/c318aa51830a3d2cc1229968fe521441c97356cd
• https://git.kernel.org/stable/c/c57ea90f203c8b8b41a474f19a09000d0f841436