Ceph: AES-CBC misuse in CephX and RADOSGW enables authentication bypass and credential forgery

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-30156
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 00:16:45 UTC
Updated2026-08-28 00:16:45 UTC
DescriptionCeph 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.

Risk And Classification

Primary CVSS: v3.1 8.9 HIGH from [email protected]

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

EPSS: 0.000930000 probability, percentile 0.006230000 (date 2026-08-29)

Problem Types: CWE-327 | CWE-327 CWE-327: Use of a Broken or Risky Cryptographic Algorithm

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.9HIGHCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
3.1CNADECLARED8.9HIGHCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Ceph Ceph affected < 19.2.6 Not specified
CNA Ceph Ceph affected >= 20.0.0, < 20.2.4 Not specified

References

ReferenceSourceLinkTags
github.com/ceph/ceph/security/advisories/GHSA-7q3q-3975-qw3q [email protected] github.com
github.com/ceph/ceph/commit/2ba086255de09c8b95177717cc7e9dd4377e2f0f [email protected] github.com
github.com/ceph/ceph/commit/3078188a7bdd89e2975280f2a906c71c2f6effd6 [email protected] github.com
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