CVE-2026-93856
Received Received - Intake

Information Disclosure in OpenStack Cinder

Publication date: 2026-10-21

Last updated on: 2026-10-21

Assigner: MITRE

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.

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Meta Information

Published
2026-10-21
Last Modified
2026-10-21
Generated
2026-11-10
AI Q&A
2026-10-21
EPSS Evaluated
2026-11-09
NVD
CVE-2026-93856
EUVD
EUVD-2026-107047

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
OpenStack Cinder 9.0.0
OpenStack Cinder 27.0.0
OpenStack Cinder 28.0.0
OpenStack Cinder 29.0.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-669 The product does not properly transfer a resource/behavior to another sphere, or improperly imports a resource/behavior from another sphere, in a manner that provides unintended control over that resource.

Attack-Flow Graph

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Executive Summary

CVE-2026-93856 is a cross-project information disclosure vulnerability in OpenStack Cinder's Messages API. A non-admin user with a project-scoped 'member' or 'reader' role can access non-expired user messages from other projects via the Block Storage API v3.3 'List messages' endpoint. While the actual messages are sanitized, the response includes UUIDs of resources owned by other projects, leading to potential information leakage across projects.

Detection Guidance

To detect this vulnerability, check if non-admin users with project-scoped 'member' or 'reader' roles can access the Cinder Messages API endpoint (GET /v3/messages). Use OpenStack CLI commands like 'openstack message list' to verify if unauthorized messages from other projects are visible. Ensure project-level filtering is applied in API responses.

Impact Analysis

This vulnerability allows low-privileged users to view sensitive operational metadata, such as resource UUIDs and failure reasons, from other projects. This could lead to unauthorized access to information about resources not owned by the user, potentially aiding in further attacks or data exfiltration. The impact is medium severity with a CVSS score of 4.3.

Compliance Impact

This vulnerability could violate compliance requirements that mandate strict data isolation and access controls, such as GDPR's data protection principles or HIPAA's safeguards for protected health information. Unauthorized cross-project data exposure risks non-compliance with these regulations, potentially leading to legal and financial penalties.

Mitigation Strategies

Apply available patches for your Cinder version from OpenDev reviews. Update to patched releases like 26.3.1, 27.0.1, 28.0.1, or 29.0.1. Alternatively, restrict access to the Messages API by enforcing stricter project scoping policies or disabling the API if not required.

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