CVE-2023-6134: Keycloak: reflected xss via wildcard in oidc redirect_uri

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-12-14 · updated 2026-09-22
Weakness: CWE-79

Description

A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is appended to the token. This issue could allow an attacker to submit a specially crafted request leading to cross-site scripting (XSS) or further attacks. This flaw is the result of an incomplete fix for CVE-2020-10748.

Affected products

Keycloak: before 22.0.7 — fixed in 22.0.7
Red Hat OpenShift Container Platform 4.18: 4.11, 4.12
RedHat Openshift Container Platform For Power: 4.9, 4.10
RedHat Openshift Container Platform Ibm Z Systems: 4.9, 4.10
Red Hat Single Sign-On: before 7.6 — fixed in 7.6

How to fix

Upgrade to a fixed version: Keycloak 22.0.7; Red Hat Single Sign-On 7.6. Check the vendor advisory for mitigations.

References

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