The Download Monitor plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 5.1.7 via the executePayment() function due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to complete arbitrary pending orders by exploiting a mismatch between the PayPal transaction token and the local order, allowing theft of paid digital goods by paying a minimal amount for a low-cost item and using that payment token to finalize a high-value order.

The Download Monitor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Cross-Origin postMessage to Admin Editor in all versions up to, and including, 5.2.10 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to trick an authenticated Administrator into visiting an attacker-controlled page that targets an open Download edit screen, after which the payload is persisted unfiltered via the Administrator's unfilteredhtml capability and later emitted verbatim to the frontend by the [downloaddata] shortcode's unescaped postcontent render path.

The Download Monitor plugin for WordPress is vulnerable to unauthorized access to functionality due to a missing capability check on the dlmuninstallplugin function in all versions up to, and including, 4.9.13. This makes it possible for authenticated attackers to uninstall the plugin and delete its data.

The Download Monitor plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the ajaxhandleapikeyactions function in all versions up to, and including, 5.0.12. This makes it possible for authenticated attackers, with Subscriber-level access and above, to revoke existing API keys and generate new ones.

The Download Monitor plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the ajaxsearchusers function in all versions up to, and including, 5.0.13. This makes it possible for authenticated attackers, with Subscriber-level access and above, to obtain usernames and emails of site users.