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CRITICAL

CVE-2026-15013

CVSS v3

9.8

CRITICAL

EPSS Score

1.5 %

exploit probability, as of 2026-09-25

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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 sec

Technical details

Published
2026-07-16
Last Modified
2026-07-16
Exploit-DB
EDB-52668

Frequently asked questions

What is 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. 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 sec

Is CVE-2026-15013 actively exploited?

Active exploitation of CVE-2026-15013 has not been confirmed. Its EPSS score was 1.5% on 2026-09-25, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-15013?

CVE-2026-15013 has a CVSS v3 base score of 9.8 (CRITICAL severity).

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