Authentication Bypass Vulnerability in SSO Login Plugin for WordPress

CVE-2026-15981

What is CVE-2026-15981?

The SAML Single Sign On – SSO Login plugin for WordPress has a vulnerability that allows unauthenticated attackers to bypass authentication mechanisms. This vulnerability arises from the mo_saml_validate_signature() function, which incorrectly evaluates the return value from PHP's openssl_verify() function. When an attacker crafts a SAMLResponse with a manipulated NameID and malformed signature, they can exploit this weakness to gain unauthorized access to existing WordPress user accounts, including those of administrators, leading to serious security breaches.

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