CVE-2026-52956 Linux CVE debrief

Who should care

Linux kernel users and distributors should be aware of this vulnerability and take steps to mitigate it. This includes updating to a patched version of the kernel or applying compensating controls to prevent exploitation. System administrators and security teams should prioritize patching or mitigating this vulnerability due to its high severity and potential for exploitation.

Technical summary

The __ceph_x_decrypt() function in the Linux kernel's libceph component does not properly validate the length of the ciphertext to decrypt, potentially leading to an out-of-bounds memory access. The function parameter ciphertext_len represents the length of the ciphertext to decrypt and is guaranteed to be at most the remaining size of the allocated buffer p. However, this value is not necessarily greater than sizeof(ceph_x_encrypt_header). A message frame of type FRAME_TAG_AUTH_REPLY_MORE with a ciphertext_len of 8 or less can trigger an out-of-bounds memory access when accessing hdr->magic. The patch fixes the issue by adding a check to ensure that the decrypted plaintext in the buffer is large enough to represent at least the ceph_x_encrypt_header.

Defensive priority

High priority should be given to patching or mitigating this vulnerability due to its high severity and potential for exploitation. Linux kernel users and distributors should update to a patched version of the kernel or apply compensating controls to prevent exploitation.

Recommended defensive actions

• Update to a patched version of the Linux kernel
• Apply compensating controls to prevent exploitation
• Monitor systems for potential exploitation attempts
• Perform thorough inventory checks to identify affected systems
• Track exceptions and implement additional security measures as needed

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, including its description, CVSS score, and references. The source item URL provides additional information on the vulnerability, including its status and references. The patch references provide information on the specific changes made to fix the vulnerability.

Official resources