CVE-2026-64405: Linux kernel · Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in b42cb640a0493d16b61ddd267420274be15efdc1 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:04 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- 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
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in b42cb640a0493d16b61ddd267420274be15efdc1, 61701912c58a05f6a043f097cc177a964abef348, 903227b6168bb99fd57d4e3c9c1b5014986198e0 +6
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn() hci_abort_conn() read hci_skb_event(hdev->sent_cmd) when a connection was pending, but hdev->sent_cmd can be NULL while req_status is still HCI_REQ_PEND, leading to a NULL pointer dereference and a general protection fault from the hci_rx_work() receive path. Instead of inspecting hdev->sent_cmd, track the in-flight create connection command with a new per-connection HCI_CONN_CREATE flag and route all cancellation through hci_cancel_connect_sync(), which dispatches to a dedicated per-type cancel function. The create command is in exactly one of two states: still queued, or in flight. The cancel function holds cmd_sync_work_lock across the whole decision: the worker takes this lock to dequeue every entry, so while it is held a queued command cannot start running and an in-flight command cannot complete and let the next command become pending. This keeps the flag test and hci_cmd_sync_cancel() atomic with respect to the worker, so a queued command is simply dequeued, and an in-flight command owned by this connection is cancelled without the risk of cancelling an unrelated command that became pending in the meantime. CIS uses the same flag mechanism via HCI_CONN_CREATE_CIS but cannot be dequeued per-connection. hci_acl_create_conn_sync() and hci_le_create_conn_sync() clear HCI_CONN_CREATE after the create command completes, but the command status handler can free conn via hci_conn_del() (for example when the controller rejects the connection) while the worker is still blocked on the connection complete event. Hold a reference on conn across the create command so the flag can be cleared without a use-after-free.
References
- git.kernel.org/stable/c/903227b6168bb99fd57d4e3c9c1b5014986198e0 (opens in a new tab)
- git.kernel.org/stable/c/83b22d7f7c384564fa42c3cf19bec715c693d7a2 (opens in a new tab)
- git.kernel.org/stable/c/70c397b62ee015e19b3924d9da741c8dda017819 (opens in a new tab)
- git.kernel.org/stable/c/61701912c58a05f6a043f097cc177a964abef348 (opens in a new tab)
- git.kernel.org/stable/c/b42cb640a0493d16b61ddd267420274be15efdc1 (opens in a new tab)
- git.kernel.org/stable/c/12917f591cea1af36087dba5b9ec888652f0b42a (opens in a new tab)