CVE-2026-64405
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Vulnerability report for CVE-2026-64405, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

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.

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a null pointer dereference in the Linux kernel's Bluetooth subsystem. It occurs in the hci_abort_conn() function when handling pending connections. The issue arises because hci_abort_conn() attempts to read hci_skb_event(hdev->sent_cmd) while hdev->sent_cmd can be NULL if a connection is still pending, leading to a crash.

Detection Guidance

This vulnerability is specific to the Linux kernel's Bluetooth subsystem and may not have direct detection commands. Monitor kernel logs for general protection faults or NULL pointer dereferences related to Bluetooth operations. Check for crashes in hci_rx_work() or hci_abort_conn() using dmesg or journalctl.

Impact Analysis

This vulnerability can cause a system crash or general protection fault when Bluetooth operations are performed. It may lead to denial of service, requiring a system reboot to restore normal operation. Users relying on Bluetooth for critical functions could experience disruptions.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for CVE-2026-64405. If immediate patching is not possible, disable Bluetooth functionality temporarily until the update is applied.

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