CVE-2023-52463

A flaw was found in the Linux kernel, which involves the improper handling of the efivarfs filesystem when the firmware does not support the SetVariable function at runtime. Specifically, even if efivarfs is initially mounted as read-only (RO), it can be remounted as read-write (RW) without checking if the firmware can handle variable updates. This issue allows operations such as efi-updatevar to be executed, which leads to a crash due to a NULL pointer dereference. This crash occurs because the callback for SetVariable is not assigned, causing a level 0 translation fault.

This vulnerability is classified as Moderate severity because it requires specific conditions to be exploited: the system must be using a firmware that does not support the SetVariable function at runtime, and an attacker must have the ability to remount the efivarfs filesystem with read-write permissions. While it does not provide direct unauthorized access or code execution, the resulting crash from a NULL pointer dereference can cause denial of service, disrupting normal system operations. The impact is limited to systems with the specified firmware and does not affect systems where the SetVariable function is properly supported, reducing the overall exposure and potential damage.

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.

No mitigation is currently available for this vulnerability. Make sure to perform the updates as they become available.