CVE-2026-16105: Auth Bypass (CVSS 4.9)

Description

A flaw was found in the RoleContainerResource component of Keycloak. The issue occurs because certain name-based endpoints in the admin REST API do not properly enforce authorization checks when managing composite roles. This allows a delegated administrator with manage-realm permissions to remove essential child roles from built-in admin roles, potentially disrupting administrative functions within a realm.

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CVSS v3.1 Score

4.9

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://access.redhat.com/security/cve/CVE-2026-16105 https://bugzilla.redhat.com/show_bug.cgi?id=2501738

Frequently Asked Questions

What is CVE-2026-16105? +

A flaw was found in the RoleContainerResource component of Keycloak. The issue occurs because certain name-based endpoints in the admin REST API do not properly enforce authorization checks when managing composite roles. This allows a delegated administrator with manage-realm permissions to remove essential child roles from built-in admin roles, potentially disrupting administrative functions within a realm. It has a CVSS v3.1 base score of 4.9 (MEDIUM).

How severe is CVE-2026-16105? +

CVE-2026-16105 has a CVSS v3.1 score of 4.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-16105? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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