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.
References7
- plugins.trac.wordpress.org/browser/miniorange-saml-20-single-si…
- plugins.trac.wordpress.org/browser/miniorange-saml-20-single-si…
- plugins.trac.wordpress.org/browser/miniorange-saml-20-single-si…
- plugins.trac.wordpress.org/browser/miniorange-saml-20-single-si…
- plugins.trac.wordpress.org/browser/miniorange-saml-20-single-si…
- plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20…
- www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea…
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 70 · as of 14 November 2026
- CWE
- CWE-287
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.