high7.3
CVE-2026-9086
Keycloak vulnerable to cross-site scripting (xss) via case-insensitive uri validation bypass
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | org.keycloak:keycloak-services | < 26.6.4 | 26.6.4 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Build Of Keycloak | from 26.4 before 26.4.13 from 26.6 before 26.6.4 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-v3f7-2p4r-mwfw
- https://github.com/keycloak/keycloak/security/advisories/GHSA-v3f7-2p4r-mwfw
- https://nvd.nist.gov/vuln/detail/CVE-2026-9086
- https://access.redhat.com/errata/RHSA-2026:30049
- https://access.redhat.com/errata/RHSA-2026:30050
- https://access.redhat.com/errata/RHSA-2026:30083
- https://access.redhat.com/errata/RHSA-2026:30084
- https://access.redhat.com/security/cve/CVE-2026-9086
- https://bugzilla.redhat.com/show_bug.cgi?id=2480170
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.json