Auth bypass in OpenStack Keystone
CVE-2026-42999
An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone RBAC policy enforcer in enforce_call unconditionally merges the raw JSON request body into the policy enforcement dictionary via policy_dict.update(json_input.copy()), overwriting trusted target data that was previously set from database lookups. Because flask.request.get_json is called with force=True, this works regardless of Content-Type or HTTP method. Any authenticated user can inject arbitrary policy target attributes (e.g., user_id, project_id) into the request body to bypass RBAC checks and perform unauthorized operations on resources belonging to other users or projects. This was introduced in commit 5ea59f52 (Rocky/14.0.0).
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (35.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- OpenStack Keystone — versions 14.0.0, 28.0.0, 29.0.0
Weakness classification (CWE)
References
- bugs.launchpad.net/keystone/+bug/2148398 (Exploit, Patch, Third Party Advisory, Issue Tracking)
- security.openstack.org/ossa/OSSA-2026-015.html (Patch, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-42999?
- CVE-2026-42999 is a medium-severity vulnerability in OpenStack Keystone, classified under Incorrect Authorization. CVSS score: 6.0/10. Published 2026-05-28.
- How severe is CVE-2026-42999?
- Medium severity. CVSS v3 base score is 6.0 out of 10.