Bug 2440300 (CVE-2026-2603) - CVE-2026-2603 keycloak: Keycloak: Unauthorized authentication via disabled SAML Identity Provider
Summary: CVE-2026-2603 keycloak: Keycloak: Unauthorized authentication via disabled SA...
Keywords:
Status: NEW
Alias: CVE-2026-2603
Deadline: 2026-03-01
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-02-16 21:18 UTC by OSIDB Bzimport
Modified: 2026-03-05 14:24 UTC (History)
9 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-02-16 21:18:59 UTC 
Summary:
A SAML Identity Provider that is disabled in the broker realm can still complete IdP‑initiated broker logins

Requirements to exploit:

The SAML protocol endpoint must be reachable
Attacker needs to know the URL assigned to the broker in Keycloak for IDP initiated
Attacker needs to log in with a valid user to the external IDP via SAML to be able to send a SAML response to Keycloak
As the SAML IDP is disabled and no longer trusted, this violates C&A for Keycloak.

Steps to reproduce:

Target a Keycloak 26.5.2 instance.
Set up an IDP in Keycloak that is disabled
Generate a valid SAML response from the external IdP
Send it to the Keycloak SAML endpoint for IDP initiated broker logins
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