libceph: Fix potential out-of-bounds access in __ceph_x_decrypt()
CVE-2026-52956 · published 24 Jun 2026
How serious is it
- Severity: high, CVSS score 7.5 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-52956?
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Who is affected
- Linux Linux: e15fd0a11db00fc7f470a9fc804657ec3f6d04a5 to < 759053333a40c6997c2917dcd6160bfe40d2b42e, e15fd0a11db00fc7f470a9fc804657ec3f6d04a5 to < ebc7eddf6225b87e3aae720875f9dd40cb6b1cef, e15fd0a11db00fc7f470a9fc804657ec3f6d04a5 to < 5df268406ef38d0f92547959296577c7077dacdc, e15fd0a11db00fc7f470a9fc804657ec3f6d04a5 to < c7e9b53aebe401970f1b5f5a01b4e021b18e8bb2
- Linux Linux: 4.10
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
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References
- git.kernel.org/stable/c/759053333a40c6997c2917dcd6160bfe40d2b42e
- git.kernel.org/stable/c/ebc7eddf6225b87e3aae720875f9dd40cb6b1cef
- git.kernel.org/stable/c/5df268406ef38d0f92547959296577c7077dacdc
- git.kernel.org/stable/c/c7e9b53aebe401970f1b5f5a01b4e021b18e8bb2
- git.kernel.org/stable/c/821365487aa58d06bda65c676ba215d506ba9768
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON