Linux Kernel: L2CAP Deadlock via pending_rx_work Cancel
CVE-2026-64206 Published on July 20, 2026
Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock
l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for
pending_rx_work. process_pending_rx() takes the same mutex, so teardown
can deadlock against the worker it is flushing.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the l2cap_conn_ready() -> queue_work(...,
&conn->pending_rx_work) submit path, the l2cap_conn_del() ->
cancel_work_sync(&conn->pending_rx_work) teardown path, and the
process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep
WARNING: possible circular locking dependency detected
process_pending_rx+0x21/0x2a [vuln_msv]
l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]
*** DEADLOCK ***
Cancel pending_rx_work before taking conn->lock, matching the existing
lock-before-drain ordering used for the two delayed works in the same
teardown path. The pending_rx queue is still purged after the work has
been cancelled and conn->lock has been acquired.
Products Associated with CVE-2026-64206
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Affected Versions
Linux:- Version 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 and below d5616beb3355b5fca2280d796c1cf7ada4ee6551 is affected.
- Version 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 and below e96fbac8d3a73b0bc165383c092a30628561d320 is affected.
- Version 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 and below 2641a9e0a1dd4af2e21995470a21d55dd35e5203 is affected.
- Version ee805f9499ebd0edf0877990968543c752043b59 is affected.
- Version 3.15.5 and below 3.16 is affected.
- Version 3.16 is affected.
- Before 3.16 is unaffected.
- Version 6.18.39, <= 6.18.* is unaffected.
- Version 7.1.4, <= 7.1.* is unaffected.
- Version 7.2-rc3, <= * is unaffected.