CVE-2026-15013
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.
Does this matter?
A public exploit is published in Exploit-DB and the impact is critical, while EPSS rates exploitation at 2.4%. Anyone can run this; patch or mitigate before the next change window and check exposed instances for signs of use.
Description
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 2.45% probability · 84th percentile
- Public exploits
- 1 in Exploit-DB · first 1 September 2026
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Source
- security@wordfence.com
EPSS 2.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.