SAML Single Sign On <= 5.4.4 - Unauthenticated Authentication Bypass via SAMLResponse Parameter
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.
Summary
The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP's openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error — bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| miniOrange | SAML Single Sign On – SSO Login | up to 5.4.4 | — | No fix listed | CNA |
- SAML Single Sign On – SSO Login VendorminiOrange Affected up to 5.4.4 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-15981
- 2026-10-03 Alias added: GHSA-wgjx-q85h-87v2
References
Other 7
- https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403
- 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#L938
- 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#L621
- https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541
- https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on
More miniOrange vulnerabilities
- TI-2023-05558 Web3 – Crypto wallet Login & NFT token gating < 3.0.0 - Authentication Bypass CVSS 3.1CRITICAL 9.8
- TI-2023-02794 WordPress Social Login and Register (Discord, Google, Twitter, LinkedIn) <= 7.6.4 - Authentication Bypass CVSS 3.1CRITICAL 9.8
- TI-2022-15071 WordPress OAuth Single Sign On – SSO (OAuth Client) Plugin <= 6.23.3 is vulnerable to Broken Authentication CVSS 3.1HIGH 8.8
- TI-2021-22592 WordPress Plugin Backup and Restore 1.0.3 Arbitrary File Deletion CVSS 4.0HIGH 8.7
- TI-2023-04605 Active Directory Integration < 4.1.10 - Unauthenticated Log Disclosure CVSS 3.1HIGH 7.5
- TI-2024-09173 Login using WordPress Users ( WP as SAML IDP ) <= 1.15.6 - Authenticated (Administrator+) SQL Injection CVSS 3.1HIGH 7.2
Sources
- CVE-2026-15981 · CVE Program
- CVE-2026-15981 · NVD
- FIRST EPSS
- GHSA-wgjx-q85h-87v2 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences