CVE-2020-25661

A Red Hat only CVE-2020-12351 regression issue was found in the way the Linux kernel's Bluetooth implementation handled L2CAP packets with A2MP CID. This flaw allows a remote attacker in an adjacent range to crash the system, causing a denial of service or potentially executing arbitrary code on the system by sending a specially crafted L2CAP packet. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

This issue only affects the Linux kernel version as shipped with the Red Hat Enterprise Linux 8.3 GA release, kernel-4.18.0-240.el8 (and any kernel derived from this release such as kernel rt-4.18.0-240.rt7.54.el8). Red Hat was unable to include the fix for the original CVE-2020-12351 issue in the GA release, as the Red Hat Enterprise Linux 8.3 GA release was in its final stages of release preparation when CVE-2020-12351 was made public. All of the subsequent Red Hat Enterprise Linux 8 kernel versions, including the version included in the so-called 0day (released on the same day or very close to that day) erratum, contain the fix, thus immune to the original CVE-2020-12351 issue.

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.

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 BIOS level which will also provide an effective mitigation as the kernel will not be able to detect that Bluetooth hardware is present on the system.