[Plugin: WP Security Scan] v2.3.8/9 breaks file uploads

Since upgrading to v2.3.8 of this plugin, I’ve been unable to upload images and have them resize (for thumbnails, etc.). They seem to fail the upload, and I get a “HTTP error” and “An error occurred in the upload. Please try again later”. However, the images actually upload, but don’t resize – and WP thinks they’re 0x0 pixels in size.

This happened on both blogs I run. In addition, I can’t unpack v2.3.9 of the plugin when I try to upgrade it automatically from the dashboard.

Disabling the plugin allows both things to work again as normal, but enabling v2.3.9 breaks image uploads again.