EUVD-2026-39471
GHSA-79qw-g39g-mfxc
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Network-reachable with low complexity; a low-privilege authenticated account suffices (PR:L); full authorization bypass yields high confidentiality and integrity impact but no availability effect (A:N).
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
1DescriptionCVE.org
A flaw was found in Keycloak Policy Enforcer. This vulnerability allows any authenticated user to bypass all authorization policies, including role, scope, and User-Managed Access (UMA) permission checks. By including the configured access-denied page path within a request URL, either as a path segment or a query parameter, an attacker can gain unauthorized access to protected resources.
AnalysisAI
Authorization bypass in the Keycloak Policy Enforcer allows any authenticated user to circumvent all enforced access controls - role, scope, and User-Managed Access (UMA) permission checks - by embedding the configured access-denied page path inside a request URL as a path segment or query parameter. The affected component ships in the Red Hat Build of Keycloak, and successful exploitation grants unauthorized access to protected resources. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV.
Technical ContextAI
Keycloak is a widely used open-source identity and access management (IAM) server; its Policy Enforcer is the adapter component that intercepts requests to protected applications and evaluates fine-grained authorization policies (role-based, scope-based, and UMA permissions) before granting access. The root cause maps to CWE-1025 (Comparison Using Wrong Factors): the enforcer matches incoming request paths against the configured access-denied page path to identify exempt/public routes, but performs this comparison too loosely - treating any URL that merely contains the access-denied path as exempt. An attacker thereby confuses policy evaluation by appending or injecting that path string, causing the enforcer to skip authorization entirely. Affected per CPE: cpe:2.3:a:red_hat:red_hat_build_of_keycloak (version wildcarded).
RemediationAI
Apply the fixed Red Hat Build of Keycloak release once published; consult the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-9800 and the tracking bug at https://bugzilla.redhat.com/show_bug.cgi?id=2482472 for the exact patched version, which is not stated in the available data (no vendor-released fix version was provided, so verify the target release directly with Red Hat before scheduling). As a compensating control until patched, do not rely solely on the Policy Enforcer's access-denied-path matching: enforce authorization at the protected application/API layer as well, and place a reverse proxy or WAF rule in front of protected endpoints that rejects requests whose path or query string contains the configured access-denied page path (side effect: legitimate links to the access-denied page itself may be blocked, so scope the rule tightly). Where feasible, change the configured access-denied page path to a hard-to-guess, non-overlapping value and audit access logs for requests containing that path string. These controls reduce exposure but do not replace the vendor patch.
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Same weakness CWE-1025 – Comparison Using Wrong Factors
View allSame technique Authentication Bypass
View allVendor StatusVendor
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