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

Source: https://junglewise.ai/threats/cve-2026-15981-miniorange-saml-single-sign-on-authentication-bypass-in-sso-login  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-23. Updated: 2026-07-23  
License: CC BY 4.0 with a link back

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

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.

Technologies: [miniOrange SAML Single Sign On – SSO Login](https://junglewise.ai/threats/technologies/saml-single-sign-on-sso-login). Vendors: [miniOrange](https://junglewise.ai/threats/vendors/miniorange).

## Quick answers

**Is CVE-2026-15981 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15981 being exploited in the wild.

**How severe is CVE-2026-15981?** Critical severity, with a CVSS score of 9.8, published 23 July 2026.

**Which products and versions are affected?** miniOrange SAML Single Sign On – SSO Login up to, and including, 5.4.4.

**Is there a fix for CVE-2026-15981?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15981 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-15981?** Check whether you run miniOrange SAML Single Sign On – SSO Login at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## 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

- [https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php](https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php)
- [https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php](https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php)
- [https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php](https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php)
- [https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php](https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php)
- [https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php](https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php)
- [https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on](https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on)
- [https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve](https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve)

## Related threats

- [miniOrange SAML Single Sign On authentication bypass](https://junglewise.ai/threats/cve-2026-75807-miniorange-saml-single-sign-on-authentication-bypass)
- [miniOrange SAML Single Sign On authentication bypass via algorithm confusion](https://junglewise.ai/threats/cve-2026-15013-miniorange-saml-single-sign-on-authentication-bypass-via)