Basel Post Types <= 1.18 — Unauthenticated Authentication Bypass via Forged Opauth Callback Signature with Hardcoded Fallback Salt

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Basel Post Types.
• 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 1.19, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Basel Post Types to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to 0xwackydawg.

The Basel Post Types plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.18. The vulnerability exists because a missing-quotes coding error in the defined() call for SECURE_AUTH_SALT inside BASEL_Auth::get_config() causes PHP to evaluate the constant's value rather than its name, making the check always fail and permanently falling back to the static hardcoded salt 2NlBUibcszrVtNmDnxqDbwCOpLWq91eatIz6O1O that is publicly visible in the theme source code; because this salt is static and known, an attacker can compute a valid Opauth signature entirely offline and submit a forged ?opauth callback to the unauthenticated init hook endpoint processed by register_or_login. This makes it possible for unauthenticated attackers to authenticate as any existing WordPress user, including administrators, by forging a callback tied to a known target account email address — bypassing all password verification, multi-factor authentication, and ownership checks, and receiving a fully authenticated session cookie via wc_set_customer_auth_cookie(). Exploitation requires WooCommerce to be active and at least one Basel social-login provider (Facebook, Google, or VKontakte) to be configured with a valid app_id and app_secret in the theme settings.

Exploits & references

Proof-of-concept & detection

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

Advisories & patches

• Advisorywordfence.com

Timeline

1. Nov 10, 2026

   CVE published

   Severity critical, CVSS 9.8

2. Nov 13, 2026

   Record last updated