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).

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2026-42999 has a CVSS score of 6.0 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (27.0.2, 28.0.2, 29.0.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-42999? CVE-2026-42999 is a medium-severity incorrect authorization vulnerability in keystone (pip), affecting versions >= 14.0.0, < 27.0.2. It is fixed in 27.0.2, 28.0.2, 29.0.2. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2026-42999? CVE-2026-42999 has a CVSS score of 6.0 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of keystone are affected by CVE-2026-42999? keystone (pip) versions >= 14.0.0, < 27.0.2 is affected.
4. Is there a fix for CVE-2026-42999? Yes. CVE-2026-42999 is fixed in 27.0.2, 28.0.2, 29.0.2. Upgrade to this version or later.
5. Is CVE-2026-42999 exploitable, and should I be worried? Whether CVE-2026-42999 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-42999 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-42999?
   • Upgrade keystone to 27.0.2 or later
   • Upgrade keystone to 28.0.2 or later
   • Upgrade keystone to 29.0.2 or later