What is CVE-2026-93856?

CVE-2026-93856 is a medium-severity vulnerability in OpenStack Cinder, classified under Incorrect Resource Transfer Between Spheres. CVSS score: 4.3/10. Published 2026-10-21.

How severe is CVE-2026-93856?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in OpenStack Cinder

CVE-2026-93856

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.

Published 2026-10-21 · last modified 2026-10-21.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

OpenStack Cinder — versions 27.0.0, 28.0.0, 29.0.0

Weakness classification (CWE)

CWE-669 — Incorrect Resource Transfer Between Spheres

References

Frequently asked questions

What is CVE-2026-93856?: CVE-2026-93856 is a medium-severity vulnerability in OpenStack Cinder, classified under Incorrect Resource Transfer Between Spheres. CVSS score: 4.3/10. Published 2026-10-21.
How severe is CVE-2026-93856?: Medium severity. CVSS v3 base score is 4.3 out of 10.