CVE-2026-19278
Description
A flaw was found in StackRox/RHACS Central's Auth Machine-to-Machine (M2M) token exchange. When an administrator configures M2M role mappings, the system uses unanchored regular expressions for matching claim values. This allows an attacker with a valid OpenID Connect (OIDC) token, whose claim value is a superstring of a configured pattern, to gain unauthorized access to roles they were not intended to receive. This can lead to privilege escalation within the system.
Statement
This Moderate severity flaw in StackRox/RHACS Central allows privilege escalation when administrators configure Auth Machine-to-Machine (M2M) role mappings with unanchored regular expressions. An attacker with a valid OIDC token and a claim value that is a superstring of a configured pattern can exploit this to obtain unintended roles, as the system performs substring matching instead of exact matching.
Mitigation
Administrators should review and update their Auth Machine-to-Machine (M2M) role mappings in StackRox/RHACS Central to ensure that `valueExpression` regular expressions are properly anchored (e.g., by adding `^` and `$` delimiters). This ensures exact matching of claim values and prevents unintended role assignments. Reloading the configuration or restarting the Central service may be required for changes to take effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.8 | N/A | 6.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Red Hat CVSS v3 Score Explanation
AC:H - exploitation requires an admin-configured M2M mapping with an unanchored pattern and the attacker's ability to obtain a valid OIDC token from a trusted issuer with a substring-matching claim value. PR:L - attacker needs some access to a trusted identity provider (e.g. repo write access to create a branch). A:N - primary impact is unauthorized access, not availability.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Acknowledgements
Red Hat would like to thank Sergey (@r0binak) Kanibor (Luntry) for reporting this issue.
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