Ceph: CephX AES Authentication error

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-39944
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 00:17:27 UTC
Updated2026-08-28 00:17:27 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 RADOS Gateway (RGW) protects STS session tokens with an AES-128-CBC handler that provides no message authentication, allowing an attacker who holds any valid STS token to tamper with it undetected and escalate to full RGW administrative access. Because the ciphertext is unauthenticated, the attacker can perform a CBC bit-flip on the acct_type, perm_type, and is_admin fields of their own token, and a forged is_admin value triggers a global administrative override that bypasses all capability checks. The attack is reachable remotely over the RGW S3 endpoint and is a self-contained modification of a token the attacker already possesses, requiring no encryption oracle and no network observation. It requires only a single valid STS token, which need not carry any elevated privileges, with STS enabled. This issue is fixed in versions 20.2.4 and 19.2.6.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

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

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Ceph Ceph affected >= 19.0.0, < 19.2.6 Not specified
CNA Ceph Ceph affected >= 20.0.0, < 20.2.4 Not specified

References

ReferenceSourceLinkTags
github.com/ceph/ceph/releases/tag/v20.2.4 [email protected] github.com
github.com/ceph/ceph/security/advisories/GHSA-j73r-qrgx-jvq2 [email protected] github.com
github.com/ceph/ceph/releases/tag/v19.2.6 [email protected] github.com
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