Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Redhat | Build Of Keycloak | >= 26.4, < 26.4.13 |
Related Weaknesses (CWE)
References
- https://access.redhat.com/errata/RHSA-2026:30049Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30050Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30083Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30084Third Party Advisory
- https://access.redhat.com/security/cve/CVE-2026-9086Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2480170Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30049Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30050Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30083Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:30084Third Party Advisory
- https://access.redhat.com/security/cve/CVE-2026-9086Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2480170Third Party Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.jsonThird Party Advisory
FAQ
What is CVE-2026-9086?
CVE-2026-9086 is a vulnerability with a CVSS score of 7.3 (HIGH). 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 Unifo...
How severe is CVE-2026-9086?
CVE-2026-9086 has been rated HIGH with a CVSS base score of 7.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-9086?
Check the references section above for vendor advisories and patch information. Affected products include: Redhat Build Of Keycloak.