Keycloak: Unauthorized authentication via disabled SAML Identity Provider
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.keycloak:keycloak-server-spi-private | < 26.5.5 | 26.5.5 |
| Java / Kotlin (Maven) | org.keycloak:keycloak-services | < 26.5.5 | 26.5.5 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-2603
- https://github.com/keycloak/keycloak/issues/46911
- https://github.com/keycloak/keycloak/pull/46932
- https://github.com/keycloak/keycloak/commit/4fd5367e6cc28cfa68fb2240fc459c12b1fdbf2a
- https://github.com/keycloak/keycloak/commit/8ed7e59dc08d79751a27c23aadb590f06b43f132
- https://access.redhat.com/errata/RHSA-2026:3925
- https://access.redhat.com/errata/RHSA-2026:3926
- https://access.redhat.com/errata/RHSA-2026:3947
- https://access.redhat.com/errata/RHSA-2026:3948
- https://access.redhat.com/security/cve/CVE-2026-2603
- https://bugzilla.redhat.com/show_bug.cgi?id=2440300
- https://github.com/keycloak/keycloak
- https://github.com/keycloak/keycloak/commits/26.5.5
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-306- Platform
- Java / Kotlin (Maven)
- Package
org.keycloak:keycloak-server-spi-private, org.keycloak:keycloak-services- Disclosed
- 18.03.2026
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-x4p7-7chp-64hq - CC BY 4.0
Vulnerability history: org.keycloak:keycloak-services
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 98
- First → latest
- 01.2022 08.2026
- Without a fix
- 16
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 26
- Medium 51
- Low 18
Disclosures per year
- 2022: 9
- 2023: 9
- 2024: 17
- 2025: 11
- 2026: 52
-
Keycloak: Unauthorized authentication via disabled SAML Identity Provider this entry
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