Summary
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.
Impact
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
CVE-2026-2603 has a CVSS score of 8.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (26.5.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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org.keycloak:keycloak-services to 26.5.5 or later; org.keycloak:keycloak-server-spi-private to 26.5.5 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-2603? CVE-2026-2603 is a high-severity missing authentication for critical function vulnerability in org.keycloak:keycloak-services (maven), affecting versions < 26.5.5. It is fixed in 26.5.5. A critical operation is accessible without requiring any authentication.
- How severe is CVE-2026-2603? CVE-2026-2603 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-2603?
org.keycloak:keycloak-services(maven) (versions < 26.5.5)org.keycloak:keycloak-server-spi-private(maven) (versions < 26.5.5)
- Is there a fix for CVE-2026-2603? Yes. CVE-2026-2603 is fixed in 26.5.5. Upgrade to this version or later.
- Is CVE-2026-2603 exploitable, and should I be worried? Whether CVE-2026-2603 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-2603 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-2603?
- Upgrade
org.keycloak:keycloak-servicesto 26.5.5 or later - Upgrade
org.keycloak:keycloak-server-spi-privateto 26.5.5 or later
- Upgrade