CVE-2026-52956

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe15fd0a11db00fc7f470a9fc804657ec3f6d04a5 < c7e9b53aebe401970f1b5f5a01b4e021b18e8bb2affected
LinuxLinuxe15fd0a11db00fc7f470a9fc804657ec3f6d04a5 < 821365487aa58d06bda65c676ba215d506ba9768affected
LinuxLinux2982b9c92a66604ffb9fb2db54cf735133d1ef56affected
LinuxLinux4.9.6 < 4.10affected
LinuxLinux4.10affected
LinuxLinux0 < 4.10unaffected
LinuxLinux7.0.10 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References