Keycloak SAML Endpoint Bypass via Crafted IdP Response
CVE-2026-2603 Published on March 18, 2026

Keycloak: 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.

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Vulnerability Analysis

CVE-2026-2603 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-2603. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
NONE

Timeline

Reported to Red Hat.

Made public. 17 days later.

Weakness Type

Missing Authentication for Critical Function

The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.


Products Associated with CVE-2026-2603

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Affected Versions

Red Hat build of Keycloak 26.2: Red Hat build of Keycloak 26.2: 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: Red Hat build of Keycloak 26.4: Red Hat build of Keycloak 26.4.10:

Exploit Probability

EPSS
0.17%
Percentile
37.90%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.