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CVE-2026-53357— Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 5.7版本存在安全漏洞，该漏洞源于蓝牙协议栈中释放后重用问题，可能导致监听套接字关闭时与HCI断开并发导致的释放后重用攻击。

CVSS 8.0 · High EPSS 0.27% · P18

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 15f02b91056253e8cdc592888f431da0731337b8< 751de6ec671fe75ad9cf65a0638d2a06b6a5984d affected
15f02b91056253e8cdc592888f431da0731337b8< 407217734835d21d4e0105ebf347860dc1806f88 affected
15f02b91056253e8cdc592888f431da0731337b8< 7eebd4c2c86f573af87ff165d08a83432eb0b919 affected
15f02b91056253e8cdc592888f431da0731337b8< 5d86d2f1b4d9a508c441d3e45277ae1a73cfed57 affected
15f02b91056253e8cdc592888f431da0731337b8< 87c543e2f78d0871f271df92dab98901bbd5b6f5 affected
15f02b91056253e8cdc592888f431da0731337b8< added1213395071470a900cc845a042fb51882a6 affected
15f02b91056253e8cdc592888f431da0731337b8< a5ca86a6097a8b030ca3226cd300b17ed330f966 affected
15f02b91056253e8cdc592888f431da0731337b8< ab1513597c6cf17cd1ad2a21e3b045421b48e022 affected
… +10 more rows
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I. Basic Information for CVE-2026-53357

Vulnerability Information
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Vulnerability Title
Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 5.7版本存在安全漏洞，该漏洞源于蓝牙协议栈中释放后重用问题，可能导致监听套接字关闭时与HCI断开并发导致的释放后重用攻击。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 15f02b91056253e8cdc592888f431da0731337b8 ~ 751de6ec671fe75ad9cf65a0638d2a06b6a5984d -
Linux Linux 5.7 -

II. Public POCs for CVE-2026-53357

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III. Intelligence Information for CVE-2026-53357

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Patches & Fixes for CVE-2026-53357 (7)

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-53357

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