CVE-2026-53252: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: fix memory leak in error path of hci_alloc_dev() Early failures in Bluetooth HCI UART configuration leak SRCU percpu memory. When device initialization fails before hci_register_dev() completes, the HCI_UNREGISTER flag is never set. As a result, when the device reference count reaches zero, bt_host_release() evaluates this flag as false and falls back to a direct kfree(hdev). Because hci_release_dev() is bypassed, the SRCU struct initialized early in hci_alloc_dev() is never cleaned up, resulting in a leak of percpu memory. Fix the leak by explicitly calling cleanup_srcu_struct() in the fallback (unregistered) branch of bt_host_release() before freeing the device.

Affected products

• Linux Linux Kernel: from 5.10.259, before 5.11 (fixed in 5.11); from 6.1.167, before 6.1.176 (fixed in 6.1.176); from 6.6.97, before 6.6.143 (fixed in 6.6.143); from 6.12.36, before 6.12.94 (fixed in 6.12.94); from 6.15.5, before 6.16 (fixed in 6.16); from 6.16.1, before 6.18.36 (fixed in 6.18.36); …

Published 2026-06-25. Last modified 2026-07-08.