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

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.

Source published

25 Apr 2024 16:02:03 UTC

Source modified

27 Oct 2026 04:28:46 UTC

Observed here

27 Oct 2026 06:22:56 UTC

Source terms

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CVSS 3.1 · 6.0 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:L