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CVE-2026-53357

Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.259, 5.15.210, 6.1.175, 6.6.142, 6.12.92, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in 751de6ec671fe75ad9cf65a0638d2a06b6a5984d; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in 407217734835d21d4e0105ebf347860dc1806f88; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in 7eebd4c2c86f573af87ff165d08a83432eb0b919; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in 5d86d2f1b4d9a508c441d3e45277ae1a73cfed57; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in 87c543e2f78d0871f271df92dab98901bbd5b6f5; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in added1213395071470a900cc845a042fb51882a6; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in a5ca86a6097a8b030ca3226cd300b17ed330f966; From 15f02b91056253e8cdc592888f431da0731337b8 · fixed in ab1513597c6cf17cd1ad2a21e3b045421b48e022

  • Linux Linux

    5.7

  • KernelLinux

    From 5.7.0 · fixed in 5.10.259; From 5.11.0 · fixed in 5.15.210; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.142; From 6.7.0 · fixed in 6.12.92; From 6.13.0 · fixed in 6.18.34; From 6.19.0 · fixed in 7.0.11

References 8

git.kernel.org