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VulnerabilityPublished Updated

CVE-2026-64206: Linux kernel · Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in fc0c3b9cf27cfa2a06f66dae1d08c668fe0a2faa : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 16% 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 fc0c3b9cf27cfa2a06f66dae1d08c668fe0a2faa, e96fbac8d3a73b0bc165383c092a30628561d320, d5616beb3355b5fca2280d796c1cf7ada4ee6551 +6
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 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
  • >=3.15.5 <3.16
Fixed in
  • fc0c3b9cf27cfa2a06f66dae1d08c668fe0a2faa
  • e96fbac8d3a73b0bc165383c092a30628561d320
  • d5616beb3355b5fca2280d796c1cf7ada4ee6551
  • 9901f847a762a5d953871dd95767ce2aed3d684d
  • 2641a9e0a1dd4af2e21995470a21d55dd35e5203
  • 8de7b386ffad480ca59222b688c94a2da8f0d805
  • 8daaf7f73fe998631a160d1a5a7e1b0b0480eef8
  • 4a0bb0fd63fe2b0c62e1072cd1811d6f61e0081c
  • 3.16
LinuxLinuxAffected
  • =3.16
Fixed in–

Description

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.

References

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