EUVD-2026-53382
GHSA-6x4h-v8cp-whwh
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
PR:L because a standard user account plus Initial Access Token is required; S:C because forged tokens grant control over other clients and realm admin scope, crossing the attacker's original authorization boundary.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Privilege escalation in Keycloak's Dynamic Client Registration (DCR) component allows attackers with standard user accounts and limited Initial Access Tokens to forge administrative roles directly into their own access tokens. The underlying flaw is a missing claim-path validation in the default DCR policy for User Property mappers, which permits writing attacker-controlled values into sensitive internal claim locations that normally carry role and privilege assertions. Successful exploitation enables takeover of other registered OAuth clients, exfiltration of confidential client secrets, and full administrative control over the affected Keycloak realm. No confirmed active exploitation or public exploit code is identified at time of analysis.
Technical ContextAI
Keycloak is Red Hat's open-source identity and access management platform, underpinning Red Hat Single Sign-On 7 and integrated into Red Hat Data Grid 8 and JBoss EAP Expansion Pack. Dynamic Client Registration (DCR) is an OAuth 2.0 protocol extension (RFC 7591) that allows software clients to register themselves programmatically with an authorization server, typically bootstrapped using a short-lived Initial Access Token issued by a realm administrator. User Property mappers are Keycloak protocol mapper plugins that extract attributes from a user record and inject them as claims into issued tokens. The root cause is that the default DCR policy omits validation of the destination claim path when a User Property mapper is submitted during client registration - an attacker can specify an internal privileged claim path (e.g., realm role membership assertions) as the mapper target. When a token is subsequently issued for the registered client, Keycloak faithfully populates the forged claim, effectively self-minting elevated privileges. Affected CPE identifiers include cpe:2.3:a:red_hat:red_hat_build_of_keycloak, cpe:2.3:a:red_hat:red_hat_single_sign-on_7, cpe:2.3:a:red_hat:red_hat_data_grid_8, and cpe:2.3:a:red_hat:red_hat_jboss_enterprise_application_platform_expansion_pack. CWE is unspecified in the advisory, but the root cause class is improper input validation combined with authorization logic bypass via claim-path traversal.
RemediationAI
Consult the Red Hat security advisory at https://access.redhat.com/security/cve/CVE-2026-16102 for the authoritative patched release - specific fix version numbers were not present in the provided intelligence data and must be retrieved directly from Red Hat (patch available per vendor advisory). As an immediate compensating control, disable Dynamic Client Registration entirely in any realm where it is not operationally required; this eliminates the vulnerable attack surface with no impact beyond forcing manual OAuth client registration workflows. If DCR must remain enabled, restrict Initial Access Token issuance exclusively to trusted realm administrators and immediately audit and revoke any IATs previously issued to standard or untrusted users - standard users should not hold tokens that grant DCR invocation rights. Audit all existing DCR-registered clients and their associated protocol mapper configurations for signs of unauthorized claim-path manipulation, particularly any User Property mappers targeting role or admin claim namespaces. Enable and review Keycloak admin event logs for anomalous client registrations or unexpected role assignments predating patch deployment.
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Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
View allVendor StatusVendor
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