CVE-2026-52956
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk28th percentile — higher than 28% of all known CVEs
Summary
In the Linux kernel's libceph, a potential out-of-bounds access was found in __ceph_x_decrypt(). The function fails to verify that the buffer is large enough to hold the ceph_x_encrypt_header structure, leading to memory read beyond allocated space.
Risk Assessment
An attacker can send a crafted authentication frame (FRAME_TAG_AUTH_REPLY_MORE) with a small ciphertext length, potentially causing system crash or sensitive data leak.
Recommendation
Apply the Linux kernel patch that adds a check ensuring the decrypted plaintext is at least the size of ceph_x_encrypt_header before accessing the header.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in __ceph_x_decrypt() In __ceph_x_decrypt(), a part of the buffer p is interpreted as a ceph_x_encrypt_header, and the magic field of this struct is accessed. This happens without any guarantee that the buffer is large enough to hold this struct. 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). E.g., a message frame of type FRAME_TAG_AUTH_REPLY_MORE, that is just as long to hold the ciphertext at its end with a ciphertext_len of 8 or less, can trigger an out-of-bounds memory access when accessing hdr->magic. This 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.