CVE-2021-32399
kernel: race condition for removal of the HCI controller
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · May 11, 2021
Updated · November 2, 2026
Description
A flaw was found in the Linux kernel’s handling of the removal of Bluetooth HCI controllers. This flaw allows an attacker with a local account to exploit a race condition, leading to corrupted memory and possible privilege escalation. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
To mitigate these vulnerabilities on the operating system level, disable the Bluetooth functionality via blocklisting kernel modules in the Linux kernel. The kernel modules can be prevented from being loaded by using system-wide modprobe rules. Instructions on how to disable Bluetooth modules are available on the Customer Portal at https://access.redhat.com/solutions/2682931.
Alternatively, Bluetooth can be disabled within the hardware or at the BIOS level which will also provide effective mitigation as the kernel will not be able to detect that Bluetooth hardware is present on the system.
CVSS / CWE
CVSS 3.1 · 7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization