CVE-2026-23461

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_register_user() and l2cap_unregister_user() to use conn->lock instead of hci_dev_lock(), ensuring consistent locking for the l2cap_conn structure.

References

• https://git.kernel.org/stable/c/11a87dd5df428a4b79a84d2790cac7f3c73f1f0d
• https://git.kernel.org/stable/c/71030f3b3015a412133a805ff47970cdcf30c2b8
• https://git.kernel.org/stable/c/752a6c9596dd25efd6978a73ff21f3b592668f4a
• https://git.kernel.org/stable/c/c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf
• https://git.kernel.org/stable/c/da3000cbe4851458a22be38bb18c0689c39fdd5f