WPCOM Member <= 1.7.27 — Unauthenticated Authentication Bypass via 'uuid' and 'code' Parameters on Social-Login Callback

Am I affected?

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

Advisory

Source description from Wordfence Intelligence, credited to Mohamed Amgad Khater (mamgad).

The WPCOM Member plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.7.27 via the `uuid` and `code` parameters of the social-login callback handler registered on the `init` hook. The vulnerability exists because the `login` function's social-login flow performs no nonce validation, no OAuth state verification, and no per-visitor namespace isolation in the session store, allowing an unauthenticated attacker to issue a crafted GET request that writes an attacker-named, attacker-valued entry into the global session namespace (bypassing the per-visitor prefix by prepending an underscore), then issue a second GET request triggering `weapp_new_user()` to read that forged entry and resolve the attacker-supplied `openid` value to a bound WordPress account before `wp_set_auth_cookie()` establishes a fully authenticated session. This makes it possible for unauthenticated attackers to log in as any WordPress user — including administrators — whose bound social provider identifier (openid/unionid) is known or discoverable. Successful exploitation requires that the target site has at least one social provider configured (which activates the vulnerable handler) and that the attacker knows or can enumerate the victim account's bound openid or unionid.

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. Oct 9, 2026

   CVE published

   Severity critical, CVSS 9.8

2. Nov 13, 2026

   Record last updated