CVE-2025-30156

Aliases:DEBIAN-CVE-2025-30156UBUNTU-CVE-2025-30156
Advisory lineage Upstream: 0 Downstream: 3
Awaiting Analysis
Published: 27 Aug 2026, 20:34
Last modified:01 Sept 2026, 03:56

Vulnerability Summary

Overall Risk (default)
medium
36/100
CVSS Score
8.9 HIGH
v3.1 (cve.org)
EPSS Score
0.09% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

27 Aug 2026, 20:34
Published
Vulnerability first disclosed
01 Sept 2026, 03:56
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•HIGH•Score: 8.9CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

EPSS Trends

Current EPSS score: 0.09%• Percentile: 1%

Techniques & Countermeasures

  • CWE-327•Use of a Broken or Risky Cryptographic Algorithm

    The product uses a broken or risky cryptographic algorithm or protocol.

Affected Systems

  • ceph•ceph

    < 19.2.6 | ≥ 20.0.0, < 20.2.4

  • debian•ceph

    all | all | all | all | < 20.2.4+ds-1

  • ubuntu•ceph

    all | all | all | all

References (7)