CVE-2025-30156
Publication date 28 August 2026
Last updated 24 September 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| ceph | 26.04 LTS resolute |
Vulnerable, fix deferred
|
| 24.04 LTS noble |
Vulnerable, work in progress
|
|
| 22.04 LTS jammy |
Vulnerable, fix deferred
|
|
| 20.04 LTS focal |
Vulnerable, fix deferred
|
|
| 18.04 LTS bionic |
Vulnerable, fix deferred
|
|
| 16.04 LTS xenial |
Vulnerable, fix deferred
|
|
| 14.04 LTS trusty |
Vulnerable, fix deferred
|
Notes
yomonokio
Fix introduces new aes256k key type across auth/mon/tools subsystems (700+ lines, 6+ core files). Cannot be isolated as a quilt patch; requires rebase to 20.2.4/19.2.6 or manual re-implementation. CVE-2026-39944 and CVE-2026-50152 both depend on this fix.
Severity score breakdown
CVSS version: CVSS v3.0
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