This vulnerability (CVE-2026-7557) arises from improper verification of cryptographic signatures in the SAML authentication module of Progress MarkLogic Server before versions 11.3.6 and 12.0.3. An unauthenticated remote attacker can exploit this flaw to bypass authentication mechanisms and impersonate any user, including administrative accounts. The issue specifically impacts environments where SAML single sign-on is enabled. The CVSS v3.1 base score is 9.1, indicating a critical severity with network attack vector, low attack complexity, no privileges required, no user interaction, and high impact on confidentiality and integrity.

Successful exploitation allows an unauthenticated remote attacker to bypass authentication controls and impersonate any user, including administrators, potentially leading to full system compromise or unauthorized access to sensitive data. The vulnerability affects confidentiality and integrity but does not impact availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, deployments with SAML single sign-on enabled should consider disabling this feature or applying any recommended temporary mitigations from Progress Software Corporation.