Security Bypass Vulnerability in Keycloak Authentication Systems
CVE-2026-2603

8.1HIGH

Key Information:

Vendor

Red Hat
Status
Red Hat Build Of Keycloak 26.2
Red Hat Build Of Keycloak 26.2.14
Red Hat Build Of Keycloak 26.4
Red Hat Build Of Keycloak 26.4.10
Vendor
CVE Published:
18 March 2026

What is CVE-2026-2603?

A vulnerability has been identified in Keycloak, which permits a remote attacker to evade security protocols by sending a legitimate SAML response from an external Identity Provider (IdP) to Keycloak's SAML endpoint. This exploit impacts the IdP-initiated broker login feature, enabling unauthorized authentication even when the SAML Identity Provider is disabled. Such an exploit could allow maladaptive parties to gain unauthorized access to sensitive resources.

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Deploy the Patch

Affected Version(s)

Red Hat build of Keycloak 26.2 26.2.14-1

Red Hat build of Keycloak 26.2 26.2-16

Red Hat build of Keycloak 26.2 26.2-16

References

https://access.redhat.com/errata/RHSA-2026:3925
vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:3926
vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:3947
vendor-advisoryx_refsource_REDHAT

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Joy Gilbert and Reynaldo Immanuel for reporting this issue.
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