The InPost PL WordPress plugin before 1.9.8 does not verify the authenticity of incoming shipment webhook requests, relying only on a non-secret identifier and an IP check that is not enforced, allowing unauthenticated attackers who know a target order's parcel tracking number to forge its shipment status and prematurely mark the order completed.

The InPost for WooCommerce plugin and InPost PL plugin for WordPress are vulnerable to unauthorized access and deletion of data due to a missing capability check on the 'parserequest' function in all versions up to, and including, 1.4.0 (for InPost for WooCommerce) as well as 1.4.4 (for InPost PL). This makes it possible for unauthenticated attackers to read and delete arbitrary files on Windows servers. On Linux servers, only files within the WordPress install will be deleted, but all files can be read.