CVE-2026-90867.3HighCWE-79

CVE-2026-9086: Keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass

Red Hat · Red Hat build of Keycloak 26.4

Vendor fix available · Affected: Red Hat build of Keycloak 26.4 · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.8%probability of exploitation in the next 30 days

56th percentile

050100

Higher than 56% of scored CVEs

7.3HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products8

From the CVE record. A product or version that is not listed is unknown, not unaffected.

Red Hat · Red Hat build of Keycloak 26.4Versions not stated
Red Hat · Red Hat build of Keycloak 26.4Versions not stated
Red Hat · Red Hat build of Keycloak 26.4Versions not stated
Red Hat · Red Hat build of Keycloak 26.4.13Versions not stated
Red Hat · Red Hat build of Keycloak 26.6Versions not stated
Red Hat · Red Hat build of Keycloak 26.6Versions not stated
Red Hat · Red Hat build of Keycloak 26.6Versions not stated
Red Hat · Red Hat build of Keycloak 26.6.4Versions not stated

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Cross-site Scripting
Vendor: Red Hat
Published: June 2026
Band: Unlikely (under 1%), June 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-9086 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.