Simplesamlphp

SimpleSAMLphp is a widely embedded open-source SAML authentication library that, despite a narrow product focus, underpins federated identity infrastructure across academic institutions, enterprises, and service providers globally. Vulnerabilities affecting the vendor skew strongly toward critical-severity outcomes and recur through weakness classes including cross-site scripting, cryptographic signature verification failures, improper input validation, and sensitive information exposure that strike at the core trust and session-management functions of a SAML implementation. The exposure concentrates in the library itself and its security modules, particularly around XML processing and signature validation, reflecting the complexity of SAML's protocol requirements and the high stakes of identity-layer flaws. Defenders should treat this vendor's security advisories as high-priority across any deployments that depend on SimpleSAMLphp for authentication, particularly in federated or multi-tenant environments where a single flaw can compromise identity trust; live exploitation and severity counts are shown alongside this summary.