CVE-2026-9086
Keycloak: keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass
CVSS Score
7.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-79 |
| Vendor | red hat |
| Product | red hat build of keycloak 26.6 |
| Published | Jun 25, 2026 |
| Last Updated | Jun 25, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Red Hat / Red Hat build of Keycloak 26.6
All versions affected Red Hat / Red Hat build of Keycloak 26.6
All versions affected Red Hat / Red Hat build of Keycloak 26.6
All versions affected Red Hat / Red Hat build of Keycloak 26.6.4
All versions affected References
Credits
Red Hat would like to thank saku0512 for reporting this issue.