CVE-2026-52957 Linux CVE debrief

Who should care

Linux kernel users and distributors should be aware of this vulnerability. The vulnerability can be exploited remotely, and its high severity (CVSS score of 7.5) indicates that it could have significant impacts on affected systems. System administrators and security teams should prioritize patching vulnerable systems.

Technical summary

The vulnerability is located in the libceph component of the Linux kernel. Specifically, it affects the decode_choose_args() function, which is responsible for decoding CRUSH maps. A CRUSH map is part of an OSD map message (CEPH_MSG_OSD_MAP). When decoding the CRUSH map, an array of max_buckets CRUSH buckets is created, and some indices may be set to NULL if they do not refer to actual buckets. The function decode_choose_args() decodes choose_args for different buckets. However, it only checks if the bucket index is within the max_buckets limit, not if the bucket is NULL. This oversight allows a potentially corrupted message to cause a null-pointer dereference when accessing the bucket with the given index.

Defensive priority

Apply the patch to update the decode_choose_args() function. Perform a thorough review of system configurations and ensure that all necessary mitigations are in place.

Recommended defensive actions

• Apply the official patch to update the decode_choose_args() function.
• Review system configurations to ensure that libceph is properly configured.
• Perform a thorough vulnerability assessment to identify potential attack vectors.
• Implement compensating controls, such as monitoring and intrusion detection, to detect potential exploitation attempts.
• Keep Linux kernel and related packages up-to-date with the latest security patches.

Evidence notes

The CVE record and NVD detail provide information on the vulnerability. The source item URL provides additional context on the vulnerability, including references to the affected code and patch information.

Official resources