Release Date: December 17, 2025Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.Component: "Single Sign-on with SAML" (md_saml)Composer Package Name: mediadreams/md_samlVulnerability Type: Authentication BypassAffected Versions: 3.0.7 and below, 4.0.0 - 4.0.4Severity: CriticalSuggested CVSS v4.0: AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NReferences: CVE-2025-66475, CWE-1395Problem Description The extension bundles the PHP package “onelogin/php-saml”, which is affected by a Authentication Bypass vulnerability via a Signature Validation Bypass vulnerability in “robrichards/xmlseclibs”. Solution Updated versions 3.0.8 and 4.0.5 are available from the TYPO3 extension manager, packagist and at https://extensions.typo3.org/extension/download/md_saml/3.0.8/ziphttps://extensions.typo3.org/extension/download/md_saml/4.0.5/zip Users of the extension are advised to update the extension as soon as possible. Credits Thanks to Christoph Daecke  for providing updated versions of the extension. General Advice Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.