CVE-2026-68085: Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work is canceled

Severity: high (CVSS 8.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-10 · updated 2026-10-19
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work is canceled HCI_UART_SENDING bit in tx_state means write_work is pending and blocks queueing it again. Currently this bit is not cleared when canceling the work in hci_uart_close(), which blocks future writes when device is reopened later if write_work was pending. Fix by clearing HCI_UART_SENDING when canceling the work. Also make clearing of tx_skb safe by using disable_work_sync + enable_work instead of just cancel_work_sync. hci_uart_flush() purges the proto tx queue so we can cancel the pending write_work there, instead of doing it just in hci_uart_close(). Re-enable and possibly requeue the work after queue flush.

Affected products

Linux kernel: from 6.12.92 before 6.12.96; from 6.18.34 before 6.18.39; from 5.10.258 before 5.11; from 5.15.209 before 5.16; from 6.1.175 before 6.2; from 6.6.142 before 6.7 — fixed in 5.11, 5.16, 6.12.96, 6.18.39, 6.2, 6.7

How to fix

Upgrade to a fixed version: Linux kernel 5.11, 5.16, 6.12.96, 6.18.39. Check the vendor advisory for mitigations.

References

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