CVE-2026-75807 SAML Single Sign On <= 5.4.6 - Unauthenticated Authentication Bypass via X.509 Certificate Poisoning
Unauthenticated attackers can bypass authentication and gain administrator access by poisoning X.509 certificates in the SAML SSO plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-75807?
CVE-2026-75807 is a high-severity authentication bypass vulnerability in cyberlord92 SAML Single Sign On – SSO Login, published on 29 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-287
Which versions are affected by CVE-2026-75807?
How do I fix CVE-2026-75807?
No fix has been published for CVE-2026-75807 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-75807 being exploited?
There is no known exploitation of CVE-2026-75807 in the wild and no public exploit code.
Sources
Also known as GHSA-2pfc-9h54-m36f.