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.
References
Configurations
Configuration 1 (hide)
|
History
22 Jul 2026, 19:06
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88 - Patch | |
| References | () https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57 - Patch | |
| References | () https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d - Patch | |
| References | () https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919 - Patch | |
| References | () https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5 - Patch | |
| References | () https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966 - Patch | |
| References | () https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022 - Patch | |
| References | () https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6 - Patch | |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* |
|
| CWE | CWE-416 | |
| First Time |
Linux linux Kernel
Linux |
18 Jul 2026, 08:16
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 8.0 |
02 Jul 2026, 15:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-07-02 15:17
Updated : 2026-07-22 19:06
NVD link : CVE-2026-53357
Mitre link : CVE-2026-53357
CVE.ORG link : CVE-2026-53357
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free