CVE-2026-53357

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del() bt_accept_dequeue() unlinks a not-yet-accepted child from the parent accept queue and release_sock()s it before returning, so the returned sk has no caller reference and is unlocked. l2cap_sock_cleanup_listen() walks these children on listening-socket close. A concurrent HCI disconnect drives hci_rx_work -> l2cap_conn_del() which runs l2cap_chan_del() + l2cap_sock_kill() and frees the child sk and its l2cap_chan; cleanup_listen() then uses both: BUG: KASAN: slab-use-after-free in l2cap_sock_kill l2cap_sock_kill / l2cap_sock_cleanup_listen / __x64_sys_close Freed by: l2cap_conn_del -> l2cap_sock_close_cb -> l2cap_sock_kill This is distinct from the two fixes already in this area: commit e83f5e24da741 ("Bluetooth: serialize accept_q access") serialises the accept_q list/poll and takes temporary refs inside bt_accept_dequeue(), and CVE-2025-39860 serialises the userspace close()/accept() race by calling cleanup_listen() under lock_sock() in l2cap_sock_release(). Neither covers l2cap_conn_del() running from hci_rx_work, so this UAF still reproduces on current bluetooth/master. Take the reference at the source: bt_accept_dequeue() does sock_hold() while sk is still locked, before release_sock(); callers sock_put(). cleanup_listen() pins the chan with l2cap_chan_hold_unless_zero() under a brief child sk lock (serialising vs l2cap_sock_teardown_cb()), drops it before l2cap_chan_lock(), and skips a duplicate l2cap_sock_kill() on SOCK_DEAD. conn->lock is not taken here: cleanup_listen() runs under the parent sk lock and that would invert conn->lock -> chan->lock -> sk_lock (lockdep). KASAN/SMP: an unprivileged listen/close vs HCI-disconnect race produced 12 use-after-free reports per run before this change; 0, and no lockdep report, over 1600+ raced iterations after it on bluetooth/master.

Gravité et risque d'exploitation

CVE-2026-53357 obtient un score CVSS de 8.0/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.27 %, ce qui la place devant 18.4 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=7.0.*, <=6.12.*, <5d86d2f1b4d9a508c441d3e45277ae1a73cfed57, 0, <7eebd4c2c86f573af87ff165d08a83432eb0b919, 5.15.210, 6.12.92, <5.7, 6.6.142, 15f02b91056253e8cdc592888f431da0731337b8, <=5.10.*, <=6.6.*, 6.1.175, <751de6ec671fe75ad9cf65a0638d2a06b6a5984d, 6.18.34, <ab1513597c6cf17cd1ad2a21e3b045421b48e022, 7.1, <=6.18.*, 7.0.11, <87c543e2f78d0871f271df92dab98901bbd5b6f5, <407217734835d21d4e0105ebf347860dc1806f88, <a5ca86a6097a8b030ca3226cd300b17ed330f966, 5.7, <=*, <=5.15.*, <added1213395071470a900cc845a042fb51882a6, 5.10.259) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d
• https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88
• https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919
• https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57
• https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5
• https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6
• https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966
• https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022