CVE-2026-53252: Bluetooth: fix memory leak in error path of hci_alloc_dev()

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: 2026-06-25 · updated 2026-07-08
Weakness: CWE-401

Description

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 kernel: from 5.10.259 before 5.11; from 6.1.167 before 6.1.176; from 6.6.97 before 6.6.143; from 6.12.36 before 6.12.94; from 6.15.5 before 6.16; from 6.16.1 before 6.18.36 — fixed in 5.11, 6.1.176, 6.12.94, 6.16, 6.18.36, 6.6.143

How to fix

Upgrade to a fixed version: Linux kernel 5.11, 6.1.176, 6.12.94, 6.16. Check the vendor advisory for mitigations.

References

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