CVE-2026-9086 | A flaw was found in Keycloak. A remote attacker with adminis… | CVSS 7.3 HIGH

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.

Metadata

CVE ID: CVE-2026-9086
State: PUBLISHED
Assigner: redhat
Reserved: 2026-05-20 14:44 UTC
Published: 2026-06-25 16:16 UTC
Last updated: 2026-06-25 17:59 UTC
Primary CWE: CWE-79
Improper Neutralization of Input During Web Page Generation …
Vendor / Product: Red Hat / Red Hat Build of Keycloak
Sources: cve.org · NVD

Severity & Metrics

7.3 HIGH CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
Red Hat	Red Hat Build of Keycloak	—	—

Weakness (CWE)

CWE	Source	Description
CWE-79	cna	Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.3	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

References (2)