Executive brief
A vulnerability was identified in the Linux kernel's Ceph storage client (libceph) that could allow a remote attacker to compromise a system. The issue stems from a lack of proper size validation when processing authentication keys, which could lead to memory corruption. An exploit could result in a complete system takeover, data theft, or a total service outage for systems using Ceph storage.
Technical details
A vulnerability exists in the libceph module of the Linux kernel due to insufficient bounds checking when decoding cryptographic keys. Specifically, the `ceph_crypto_key_decode` function did not enforce a maximum length for key material, which is subsequently used in `process_auth_done()` to fill a fixed-size stack buffer (`session_key_buf`). A remote attacker could provide a specially crafted authentication key that exceeds the expected 16-byte limit, leading to a buffer overflow. This could result in arbitrary code execution or a kernel panic (DoS). The fix introduces and enforces `CEPH_MAX_KEY_LEN` to ensure key material fits within allocated buffers.
Affected products
- Linux Linux Kernel All versions prior to the 2026-03-04 patches
Timeline
- 2025-07-04: other: Initial fix authored
- 2026-02-09: other: Fix committed to mainline kernel
- 2026-03-04: patched: Fix backported to various stable kernel branches
- 2026-05-08: disclosed: CVE published
References
- https://git.kernel.org/stable/c/1b275bd49e58752efb83767a5d1aed41356c5e64
- https://git.kernel.org/stable/c/6405e8c680974bb74e2c98d5249fb52c7b12a6c6
- https://git.kernel.org/stable/c/8d745d38c88ecbed95f6b2b39857bf89f35a3244
- https://git.kernel.org/stable/c/ac431d597a9bdfc2ba6b314813f29a6ef2b4a3bf
- https://git.kernel.org/stable/c/c1a0f5f1e5e7e98c36a362ec3d1fcfd9932931ed
- https://git.kernel.org/stable/c/d82467c07b03a27c3c5469b62bb3b726305a80bb
- https://git.kernel.org/stable/c/e1dc45d97975f9db65694d234fbddf1915176e16