CVE-2026-15013The 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.
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No exploitation reported and no EPSS estimate yet.
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.
- CVSS
- 9.8 CRITICAL (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-347
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Deferred
- Record last updated
- Aug 7, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
No affected products are listed yet.
References
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.3/class-mo-saml-login-validate.php#L119
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.3/class-mo-saml-utilities.php#L416
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.3/class-mo-saml-utilities.php#L444
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.3/class-mo-saml-utilities.php#L561
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.3/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php#L722
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3601345%40miniorange-saml-20-single-sign-on&new=3601345%40miniorange-saml-20-single-sign-on
- https://www.wordfence.com/threat-intel/vulnerabilities/id/ee95092d-6351-4612-872d-284165bc1201?source=cve
- http://seclists.org/fulldisclosure/2026/Aug/33
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.