CVE-2023-6717: Keycloak: xss via assertion consumer service url in saml post-binding flow

Severity: medium (CVSS 6.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-25 · updated 2026-10-27
Weakness: CWE-79

Description

A flaw was found in the SAML client registration in Keycloak that could allow an administrator to register malicious JavaScript URIs as Assertion Consumer Service POST Binding URLs (ACS), posing a Cross-Site Scripting (XSS) risk. This issue may allow a malicious admin in one realm or a client with registration access to target users in different realms or applications, executing arbitrary JavaScript in their contexts upon form submission. This can enable unauthorized access and harmful actions, compromising the confidentiality, integrity, and availability of the complete KC instance.

Affected products

Keycloak: before 22.0.10; from 24.0.0 before 24.0.3 — fixed in 22.0.10, 24.0.3
Red Hat Migration Toolkit for Applications 6: all versions
Red Hat build of Apicurio Registry 2: all versions
Red Hat build of Keycloak 22: all versions — fixed in 22.0.10-1
Red Hat Data Grid 8: all versions
Red Hat Decision Manager 7: all versions
Red Hat Fuse 7: all versions
Red Hat JBoss Data Grid 7: all versions
Red Hat OpenShift GitOps: all versions
Red Hat Process Automation 7: all versions
Red Hat Single Sign-On 7: all versions
Red Hat RHOSS-1.33-RHEL-8: all versions — fixed in 1.33.0-5

How to fix

Upgrade to a fixed version: Keycloak 22.0.10, 24.0.3; Red Hat build of Keycloak 22 22.0.10-1; Red Hat RHOSS-1.33-RHEL-8 1.33.0-5. Check the vendor advisory for mitigations.

References

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