CVE-2026-19842: Unknown SAML Single Sign On

High severity, CVSS 8.8. EPSS: 0.3% chance of exploitation in the next 30 days.

The SAML Single Sign On WordPress plugin before 5.4.7 does not verify the signature of a SAML response before storing the certificate it carries, and offers an administrator a one-click control that promotes that stored certificate to the site's trusted signing certificate, allowing unauthenticated attackers to have a certificate of their own trusted and then authenticate as any user, including an administrator.

Affected products

• Unknown SAML Single Sign On: from 4.8.85, before 5.4.7 (fixed in 5.4.7)

Published 2026-08-19. Last modified 2026-08-26.