Vulnerability · Published Oct 21, 2026 · Assigned by mitre
CVE-2026-93856
Medium 4.3
In plain English
A medium-severity security flaw in Cinder from OpenStack. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In OpenStack Cinder through 29.0.0, cross-project information disclosure can occur in the Messages API. A non-admin user with the project-scoped 'member' or 'reader' role making the Block Storage API v3.3 "List messages" call finds the non-expired user messages for other projects included in the response, resulting in the leakage of UUIDs of resources owned by other projects, in addition to the user message about the other projects' resources (which, by design, are sanitized generic messages). All Cinder deployments are affected.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | cinder | no fix listed | DEBIAN-CVE-2026-93856 |
| Debian:13 | cinder | no fix listed | DEBIAN-CVE-2026-93856 |
| Debian:14 | cinder | 2:29.0.0-3 | DEBIAN-CVE-2026-93856 |
| Ubuntu:22.04:LTS | cinder | no fix listed | UBUNTU-CVE-2026-93856 |
| Ubuntu:24.04:LTS | cinder | no fix listed | UBUNTU-CVE-2026-93856 |
| Ubuntu:26.04:LTS | cinder | no fix listed | UBUNTU-CVE-2026-93856 |
| Ubuntu:26.10 | cinder | no fix listed | UBUNTU-CVE-2026-93856 |
Affected products (as reported)
Weakness: CWE-669 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N