CVE-2026-53357 is a vulnerability in Linux Kernel
Published on July 2, 2026
Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()
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.
Products Associated with CVE-2026-53357
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Affected Versions
Linux:- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 751de6ec671fe75ad9cf65a0638d2a06b6a5984d is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 407217734835d21d4e0105ebf347860dc1806f88 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 7eebd4c2c86f573af87ff165d08a83432eb0b919 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 5d86d2f1b4d9a508c441d3e45277ae1a73cfed57 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 87c543e2f78d0871f271df92dab98901bbd5b6f5 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below added1213395071470a900cc845a042fb51882a6 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below a5ca86a6097a8b030ca3226cd300b17ed330f966 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below ab1513597c6cf17cd1ad2a21e3b045421b48e022 is affected.
- Version 5.7 is affected.
- Before 5.7 is unaffected.
- Version 5.10.259, <= 5.10.* is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.