Duplicate Advisory: Keycloak vulnerable to cross-site scripting (xss) via case-insensitive uri validation bypass
Severity: high · CVSS 7.3 · Published 2026-06-25
### Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-v3f7-2p4r-mwfw. This link is maintained to preserve external references.
### Original 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.
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
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