CVE-2026-53357

Status: AnalyzedHigh (8)—

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:

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().

Read full descriptionShow less

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.

Technical details traces, logs and code from the original report

  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

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.41%
Percentile among all scored CVEs: 33
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1210 Exploitation of Remote Serviceslateral movement45 %
Primary impactT1499.004 Application or System Exploitationimpact70 %

Vulnerabilidad UAF en kernel Bluetooth (AV:A/PR:L) en red adyacente; impacto es DoS por crash/kernel panic al liberar memoria en uso.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability Scanning Threat Intelligence Program Privileged Account Management Network Segmentation Filter Network Traffic Disable or Remove Feature or Program

Affected technologies (1)

Linux — Linux Kernel

CWEs

CWE-416

References

Raw JSON (NVD)

Show

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