CVE-2026-2603 Keycloak: keycloak: unauthorized authentication via disabled saml identity provider
Attackers can bypass authentication controls by sending valid SAML responses to disabled identity providers, allowing unauthorized broker logins in Keycloak.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-2603?
CVE-2026-2603 is a high-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 18 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-306
Which versions are affected by CVE-2026-2603?
5 open source packages ship an affected version, including org.keycloak:keycloak-server-spi-private, keycloak and org.keycloak:keycloak-services. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-server-spi-private Maven | All versions | 26.5.5 |
org.keycloak:keycloak-server-spi-private Maven | All versions | 26.5.5 |
keycloak Bitnami | From 26.2.0 | 26.2.14, 26.4.10 |
org.keycloak:keycloak-services Maven | All versions | 26.5.5 |
org.keycloak:keycloak-services Maven | All versions | 26.5.5 |
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-2603?
Upgrade org.keycloak:keycloak-server-spi-private to 26.5.5 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-2603 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2603 exists.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as BIT-keycloak-2026-2603, ECHO-3d2b-de07-3bbe, GHSA-x4p7-7chp-64hq, MINI-2cvf-xw78-78f4, MINI-jv86-43mf-v9w2.