Description
A flaw was found in Keycloak. A remote attacker could bypass security controls by sending a valid SAML response from an external Identity Provider (IdP) to the Keycloak SAML endpoint for IdP-initiated broker logins. This allows the attacker to complete broker logins even when the SAML Identity Provider is disabled, leading to unauthorized authentication.
Affected products
redhat: build of keycloak
References10
- access.redhat.com/errata/RHSA-2026:3925 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3926 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3947 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3948 Vendor Advisory
- access.redhat.com/security/cve/CVE-2026-2603 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2440300 ExploitIssue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:3925 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3926 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3947 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3948 Vendor Advisory
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 40 · as of 12 November 2026
- CWE
- CWE-306
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.