CVE-2026-16102: Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-08-31
Weakness: CWE-551

Description

A flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management solution. The default DCR policy fails to properly validate the claim path for User Property mappers, allowing them to write values to sensitive internal claim locations. An attacker with a standard user account and a limited Initial Access Token can exploit this to forge administrative roles in their access token. This allows the attacker to take over other clients, steal confidential secrets, and potentially gain full administrative control over the realm.

Affected products

Red Hat build of Keycloak 26.4: from 26.4 before 26.4.14; from 26.6 before 26.6.5 — fixed in 26.4.14, 26.6.5
RedHat Data Grid: 8.0
RedHat Jboss Enterprise Application Platform Expansion Pack: all versions
Red Hat Single Sign-On: 7.0

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4.14, 26.6.5. Check the vendor advisory for mitigations.

References

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