CVE-2026-42998

An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone application credential authentication plugin does not verify that the user supplied in the authentication request matches the owner of the application credential. An attacker can authenticate with their own application credential ID and secret while specifying a different user's name and domain in the request body. Keystone issues a token attributed to the victim user. The impersonated token is project-scoped and carries the intersection of the application credential's roles and the victim's actual roles on the project. This enables audit evasion, reading the victim's credentials, and acting as the victim within shared projects.

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-2026-42998 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-2026-42998? CVE-2026-42998 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-2026-42998? CVE-2026-42998 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-2026-42998? keystone (pip) versions >= 14.0.0, < 27.0.2 is affected.
4. Is there a fix for CVE-2026-42998? Yes. CVE-2026-42998 is fixed in 27.0.2, 28.0.2, 29.0.2. Upgrade to this version or later.
5. Is CVE-2026-42998 exploitable, and should I be worried? Whether CVE-2026-42998 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-2026-42998 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-2026-42998?
   • Upgrade keystone to 27.0.2 or later
   • Upgrade keystone to 28.0.2 or later
   • Upgrade keystone to 29.0.2 or later