CVE-2026-15013

Summary

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.

Affected Software

VendorProductVersion RangeStatus
cyberlord92SAML Single Sign On – SSO Login0 <= 5.4.3affected

Weaknesses

  • CWE-347: CWE-347 Improper Verification of Cryptographic Signature

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: total

References