CVE-2026-2603
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.43% probability · 36th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-306
- Affected
- redhat/build of keycloak
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:3925Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3926Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3947Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3948Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-2603Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2440300Exploit, Issue Tracking, Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3925Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3926Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3947Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:3948Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-2603Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2440300Exploit, Issue Tracking, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2440300Exploit, Issue Tracking, Vendor Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2603.jsonVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.