Junglewise Threat Intelligence

CVE-2026-15981: miniOrange SAML Single Sign On authentication bypass in SSO Login plugin

CVE-2026-15981 · Severity: critical · CVSS 9.8 · Published 2026-07-23

Technologies: miniOrange SAML Single Sign On – SSO Login. Vendors: miniOrange.

Executive brief

The SAML Single Sign On – SSO Login plugin for WordPress, which allows users to log into websites using external identity providers, contains a critical security flaw. This vulnerability allows an attacker to bypass the login process and gain full access to any user account, including administrator accounts, without needing a password. This could lead to a complete takeover of the website, theft of sensitive customer data, or disruption of business operations.

Technical details

The vulnerability exists in the mo_saml_validate_signature() function due to an improper check of the return value from PHP's openssl_verify() function. The plugin performs a loose boolean check on the raw tri-state integer returned by OpenSSL; specifically, it treats an error value of -1 as truthy, which is interpreted as a successful signature verification. An unauthenticated attacker can exploit this by sending a crafted SAMLResponse with a malformed signature that triggers an OpenSSL processing error. This bypasses the cryptographic verification entirely, allowing the attacker to impersonate any user via the NameID field and gain an authenticated session via wp_set_auth_cookie().

Affected products

  • miniOrange SAML Single Sign On – SSO Login up to, and including, 5.4.4

Timeline

  • 2026-07-23: disclosed
  • 2026-07-23: advisory

References

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