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

WordPress · CVE-2026-104803
0 news outlets0 CERTs and agencies0 researchers

What is it?

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 vulner

Evidence

No coverage recorded yet.

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
9.8
EPSS
0.4%
First seen
8 h ago
Status
corroborated

All WordPress vulnerabilities