CVE-2025-30156: Ceph is an open-source distributed storage platform providing object, block, and file storage
CVE-2025-30156 analysis covering impact, affected products, versions, remediation, and cross-checked defender guidance.
CVE-2025-30156 is a vulnerability published by NVD on 8/28/2026.
What happened
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.
Affected products and versions
- NVD has not published a normalized affected-product configuration yet.
Severity and weakness
CVSS: HIGH 8.9. Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L.
Weaknesses: CWE-327.
Known exploitation
No CISA KEV entry is currently attached to the NVD record.
What defenders should do
- Identify whether the affected product and version range exists in production.
- Review vendor advisories and release notes before change windows.
- Patch, upgrade, disable the vulnerable component, or apply vendor mitigations.
- Verify the running version after deployment, not only the package inventory.
Official and supporting references
- No vendor advisory tagged by NVD at draft time.