{"id":"CVE-2026-15981","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-15981","summary":"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()…","details":"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.","published":"2026-07-23T21:17:03.220","modified":"2026-07-24T23:16:50.257","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118"},{"type":"WEB","url":"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541"},{"type":"WEB","url":"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403"},{"type":"WEB","url":"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php#L938"},{"type":"WEB","url":"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php#L621"},{"type":"WEB","url":"https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on"},{"type":"WEB","url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-07-24T23:16:50.257"}}