What the vulnerability does
01Description
The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass via SAML Signature Algorithm Confusion in all versions up to, and including, 5.4.3. The vulnerability exists because `Mo_SAML_Utilities::mo_saml_cast_key()` reads the `SignatureMethod` Algorithm attribute directly from the attacker-controlled `SAMLResponse` parameter rather than enforcing the locally configured algorithm, causing the plugin to recast the IdP's RSA public key as an HMAC-SHA1 shared secret and validate the forged signature against it. This makes it possible for unauthenticated attackers to forge a SAML assertion targeting any WordPress account — including administrators — obtain valid WordPress authentication cookies, and achieve full administrator-level account takeover.
Explanation of Vulnerability in Simple Terms
02Summary
The SAML Single Sign On plugin fails to properly verify cryptographic signatures on SAML assertions. An attacker can forge authentication tokens without valid credentials, gaining unauthorized access to any account on the site. No user interaction or authentication is required. This affects all versions up to 5.4.3.
What an attacker can do
03Attacker Capabilities
Forge SAML authentication tokens to log in as any user, including administrators.
Potential impact on your site
04Site Impact
Attackers can take over any user account, including admin accounts, without knowing passwords.
Conditions required to exploit
05Prerequisites
Network access to the site; no authentication or user interaction required.
Key dates
06Disclosure timeline
July 16, 2026
CVE published
August 7, 2026
Record updated
