OAuth Single Sign On – SSO (OAuth Client) <= 7.1.2 — Unauthenticated Authentication Bypass

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under OAuth Single Sign On – SSO (OAuth Client).
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. Update to version 7.1.3, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch OAuth Single Sign On – SSO (OAuth Client) to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to rpgsec.

The OAuth Single Sign On – SSO (OAuth Client) plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 7.1.2. This is due to missing enforcement of the email-verification claim when the claim is absent from the IdP response, because the old inline check was gated on isset($resource_owner[$idp_email_verified_key]) and skipped silently when the claim was not present. This makes it possible for unauthenticated attackers to gain access to an account without a verified email address by authenticating through an OAuth provider that omits the email-verification claim from its response, causing the verification check to be silently bypassed. The 'email verified' check must be enabled in the plugin settings (mo_oauth_email_verify_check).

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. Sep 30, 2026

   CVE published

   Severity medium, CVSS 5.3

2. Nov 13, 2026

   Record last updated