WPGSI: Spreadsheet Integration <= 3.8.3 - Missing Authorization to Unauthenticated Arbitrary Post Creation and Deletion via Forged Base64 Token

The WPGSI: Spreadsheet Integration plugin for WordPress is vulnerable to unauthorized modification and loss of data due to missing capability checks and an insecure authentication mechanism on the `wpgsi_callBackFuncAccept` and `wpgsi_callBackFuncUpdate` REST API functions in all versions up to, and including, 3.8.3. Both REST endpoints use `permission_callback => '__return_true'`, allowing unauthenticated access. The plugin's custom token-based validation relies on a Base64-encoded JSON object containing the user ID and email address, but is not cryptographically signed. This makes it possible for unauthenticated attackers to forge tokens using publicly enumerable information (admin user ID and email) to create, modify, and delete arbitrary WordPress posts and pages, granted they know the administrator's email address and an active integration ID with remote updates enabled.

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: WPGSI 3.8.4 closes this, and updating the plugin is the step that ends it.

• Login Security
• Alerts