CVE-2026-53073: Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-24 · updated 2026-07-21
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error When hci_register_dev() fails in hci_uart_register_dev() HCI_UART_PROTO_INIT is not cleared before calling hu->proto->close(hu) and setting hu->hdev to NULL. This means incoming UART data will reach the protocol-specific recv handler in hci_uart_tty_receive() after resources are freed. Clear HCI_UART_PROTO_INIT with a write lock before calling hu->proto->close() and setting hu->hdev to NULL. The write lock ensures all active readers have completed and no new reader can enter the protocol recv path before resources are freed. This allows the protocol-specific recv functions to remove the "HCI_UART_REGISTERED" guard without risking a null pointer dereference if hci_register_dev() fails.

Affected products

Linux kernel: from 5.4.293 before 5.5; from 5.10.237 before 5.10.258; from 5.15.181 before 5.15.209; from 6.1.135 before 6.1.175; from 6.6.88 before 6.6.141; from 6.12.24 before 6.12.91 — fixed in 5.10.258, 5.15.209, 5.5, 6.1.175, 6.12.91, 6.14

How to fix

Upgrade to a fixed version: Linux kernel 5.10.258, 5.15.209, 5.5, 6.1.175. Check the vendor advisory for mitigations.

References

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