# Duplicate Advisory: Keycloak vulnerable to cross-site scripting (xss) via case-insensitive uri validation bypass

Source: https://junglewise.ai/threats/duplicate-advisory-keycloak-vulnerable-to-cross-site-scripting-xss-via-1687acae  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25  
License: CC BY 4.0 with a link back

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This advisory has been withdrawn because it is a duplicate of GHSA-v3f7-2p4r-mwfw.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.

Technologies: [org.keycloak:keycloak-services (Maven)](https://junglewise.ai/threats/technologies/org-keycloak-keycloak-services). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** High severity, with a CVSS score of 7.3, published 25 June 2026.

**Which products and versions are affected?** org.keycloak:keycloak-services (Maven) < 26.6.4, ECOSYSTEM:introduced=0.

**Is there a fix for This vulnerability?** 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.

**Am I affected?** Check whether you run org.keycloak:keycloak-services (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- org.keycloak:keycloak-services (Maven) < 26.6.4, ECOSYSTEM:introduced=0

## Related threats

- [Keycloak unauthenticated account takeover via reset-credentials bypass](https://junglewise.ai/threats/cve-2026-18963-siemens-industrial-edge-management-authentication-bypass-in)
- [Duplicate Advisory: Authentication bypass via jwt algorithm confusion](https://junglewise.ai/threats/duplicate-advisory-authentication-bypass-via-jwt-algorithm-confusion-40489dee)
- [Keycloak JWT algorithm confusion in JWT Authorization Grant flow](https://junglewise.ai/threats/cve-2026-11800-keycloak-jwt-algorithm-confusion-in-jwt-authorization-grant-flow)
- [Duplicate Advisory: Keycloak vulnerable to authorization bypass via incorrect uri comparison](https://junglewise.ai/threats/duplicate-advisory-keycloak-vulnerable-to-authorization-bypass-via-009d6a49)
- [Duplicate Advisory: Keycloak allows unauthorized access to resources via uma permission ticket bypass](https://junglewise.ai/threats/duplicate-advisory-keycloak-allows-unauthorized-access-to-resources-via-1f5f5b83)