CVE-2026-75807: SAML Single Sign On <= 5.4.6 - Unauthenticated Authentication Bypass via X.509 Certificate Poisoning

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 10 Nov 2026.

VulnCheck KEV lists it since 4 Nov 2026. It cites 1 public report, the first from 4 Nov 2026.

• patchstack.com

How likely is exploitation in the next 30 days?

0.4%

EPSS score, percentile 35.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

7.5 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

No patch or vendor advisory is listed in the CVE record. Check cyberlord92's advisories.

Which versions are affected?

Affected

• 5.4.6 and earlier

Versions by product

Source: CISA KEV 2026.11.10, as of 10 Nov 2026; VulnCheck KEV, as of 12 Nov 2026; FIRST EPSS, as of 12 Nov 2026; CVE List, as of 12 Nov 2026. About the data.

Description

SAML Single Sign On <= 5.4.6 - Unauthenticated Authentication Bypass via X.509 Certificate Poisoning

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in versions up to, and including, 5.4.6. This is due to the mo_saml_login_validate() ACS handler persisting the X.509 certificate extracted from an incoming SAMLResponse into the mo_saml_required_certificate option before the signature-validation verdict is enforced, because mo_saml_find_certificate() returns false on a fingerprint mismatch rather than halting execution. This makes it possible for unauthenticated attackers to overwrite the plugin's stored IdP signing certificate with an attacker-controlled value, and subsequently forge SAML assertions for any WordPress account — including administrators — to obtain a fully privileged session. Note: The exploit requires the administrator to perform a repair after receiving the test_config_error_wpsamlerr004 error message during the test configuration.

Source: CVE List, as of 12 Nov 2026. About the data.

What to do

Advisories and patches

No patch, vendor advisory or mitigation is listed in the CVE record. Check cyberlord92's own security advisories for a fix, and compare your version with the affected versions below.

This summary is based on the CVE record as of 12 Nov 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 12 Nov 2026. About the data.

Timeline