Keycloak on Red Hat Requests insufficient granularity of access control

Summaryinfo

A vulnerability identified as problematic has been detected in Keycloak on Red Hat. This affects an unknown function of the component Requests Handler. The manipulation leads to insufficient granularity of access control. This vulnerability is referenced as CVE-2026-37981. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Keycloak on Red Hat (affected version not known). It has been rated as problematic. This issue affects some unknown functionality of the component Requests Handler. The manipulation with an unknown input leads to a insufficient granularity of access control vulnerability. Using CWE to declare the problem leads to CWE-1220. The product implements access controls via a policy or other feature with the intention to disable or restrict accesses (reads and/or writes) to assets in a system from untrusted agents. However, implemented access controls lack required granularity, which renders the control policy too broad because it allows accesses from unauthorized agents to the security-sensitive assets. Impacted is confidentiality. The summary by CVE is:

A flaw was found in Keycloak. A broken access control vulnerability in the Account Resources user lookup endpoint allows a remote authenticated user, who owns at least one User-Managed Access (UMA) resource, to enumerate and harvest personally identifiable information (PII) for all realm users. By sending crafted requests with arbitrary usernames or email values, the endpoint returns full profile objects for unrelated users. This leads to broad profile-level information disclosure.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-37981 since 04/06/2026. The exploitation is known to be easy. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1612). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Red Hat Enterprise Linux
• Open Source Keycloak

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• Keycloak

License

• open-source

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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