CVE-2026-2092 is a vulnerability identified in the Red Hat build of Keycloak version 26.2, specifically affecting the Security Assertion Markup Language (SAML) broker endpoint. The flaw arises because Keycloak does not properly validate encrypted assertions within a SAML response if the overall response itself is not signed. In typical SAML workflows, assertions and responses are signed to ensure authenticity and integrity. However, this vulnerability allows an attacker who already possesses a valid signed SAML assertion to craft a malicious SAML response that includes an encrypted assertion for an arbitrary principal (user). Because the system fails to validate the encrypted assertion correctly under these conditions, the attacker can inject this assertion and gain unauthorized access to the system as that arbitrary user. This can lead to unauthorized access to protected resources and potential information disclosure. The vulnerability has a CVSS v3.1 score of 7.7, reflecting high severity, with attack vector being network-based, requiring low privileges, no user interaction, and a scope change due to compromised confidentiality and partial integrity and availability impacts. No known exploits have been reported in the wild so far. The vulnerability affects identity and access management systems relying on Keycloak 26.2, which is widely used in enterprise and cloud environments for SAML-based single sign-on (SSO).

The primary impact of CVE-2026-2092 is unauthorized access to systems protected by Keycloak 26.2 using SAML authentication. Attackers can impersonate arbitrary users by injecting malicious encrypted assertions, potentially accessing sensitive data or performing unauthorized actions. This compromises confidentiality by exposing protected information, integrity by allowing unauthorized user impersonation, and availability by potentially disrupting normal authentication flows. Organizations relying on Keycloak for identity federation, especially those integrating with critical business applications or cloud services, face elevated risk of data breaches and privilege escalation. The vulnerability's network-based attack vector and low privilege requirement increase the likelihood of exploitation in environments where attackers have some network access. Although no exploits are currently known in the wild, the high severity score and the critical role of Keycloak in authentication make this a significant threat to organizations worldwide.

To mitigate CVE-2026-2092, organizations should immediately upgrade to a patched version of Red Hat's Keycloak build once available, as this is the most effective remediation. In the interim, administrators should enforce strict validation of SAML responses by configuring Keycloak to require signed SAML responses in addition to signed assertions, thereby preventing acceptance of unsigned responses containing malicious encrypted assertions. Review and tighten SAML broker endpoint configurations to limit acceptance of external assertions only from trusted identity providers. Implement network segmentation and access controls to restrict network access to Keycloak endpoints, reducing exposure to potential attackers. Monitor authentication logs for anomalous SAML assertions or unexpected user access patterns that could indicate exploitation attempts. Additionally, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block malformed or suspicious SAML responses. Regularly audit and update identity federation configurations to adhere to best security practices and reduce attack surface.