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VulnerabilityPublished Updated

CVE-2026-53357: Linux kernel · Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()

Affects Linux kernelSource CVE Database V5

0

Mentioned vulnerabilities

Not known to be exploited · CVSS 8.0 High · fixed in added1213395071470a900cc845a042fb51882a6 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
8.0High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in added1213395071470a900cc845a042fb51882a6, ab1513597c6cf17cd1ad2a21e3b045421b48e022, a5ca86a6097a8b030ca3226cd300b17ed330f966 +5
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < added1213395071470a900cc845a042fb51882a6
Fixed in
  • added1213395071470a900cc845a042fb51882a6
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < ab1513597c6cf17cd1ad2a21e3b045421b48e022
Fixed in
  • ab1513597c6cf17cd1ad2a21e3b045421b48e022
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < a5ca86a6097a8b030ca3226cd300b17ed330f966
Fixed in
  • a5ca86a6097a8b030ca3226cd300b17ed330f966
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < 407217734835d21d4e0105ebf347860dc1806f88
Fixed in
  • 407217734835d21d4e0105ebf347860dc1806f88
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < 751de6ec671fe75ad9cf65a0638d2a06b6a5984d
Fixed in
  • 751de6ec671fe75ad9cf65a0638d2a06b6a5984d
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < 87c543e2f78d0871f271df92dab98901bbd5b6f5
Fixed in
  • 87c543e2f78d0871f271df92dab98901bbd5b6f5

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.

References

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