Vulnerability in Ceph
CVE-2025-30156
Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the CephX authentication protocol encrypts tickets with AES-128-CBC in an unauthenticated mode that uses a hard-coded initialization vector and no message authentication, allowing an attacker to forge credentials and gain cluster-wide access. Because the ciphertext is malleable and the monitor will encrypt attacker-chosen entity names, an attacker holding one low-privilege key and able to observe CephX traffic can use the monitor as an encryption oracle and splice ciphertext blocks into valid tickets for privileged entities such as Manager, MDS, and OSD. The same lack of authentication also lets an attacker with CephX permissions escalate privileges by flipping a single bit in a service ticket to set its allow_all field to true. This issue is fixed in versions 20.2.4 and 19.2.6.
Vulnerability class: POODLE (CVE-2014-3566)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.9 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.001 (0.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 0.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Ceph — versions < 19.2.6, >= 20.0.0, < 20.2.4
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2025-30156?
- CVE-2025-30156 is a high-severity vulnerability in Ceph, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 8.9/10. Published 2026-08-28.
- How severe is CVE-2025-30156?
- High severity. CVSS v3 base score is 8.9 out of 10.