{"cvss":0.0,"datePublished":"2026-08-21T00:00:00Z","dateUpdated":"2026-08-21T00:00:00Z","description":"The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP's openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error — bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.","dueDate":"","id":"CVE-2026-15981","kev_catalogs":["vulncheck"],"knownRansomwareCampaignUse":"Unknown","product":"saml_sp_single_sign_on","requiredAction":"Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.","severity":"HIGH","source":"vulncheck_kev","title":"MiniOrange saml_sp_single_sign_on Improper Authentication","vendor":"MiniOrange"}