Deep-Dive Technical Write-up by Huynh Kien Minh: CVE-2026-13157 — Theme Demo Import Arbitrary File Upload to Remote Code Execution

The Theme Demo Import WordPress plugin (prior to 1.1.3) has a vulnerability that allows authenticated users to upload arbitrary files, leading to Remote Code Execution (RCE). This is due to the plugin disabling WordPress's file-type verification tests during upload processing. To mitigate this, update the plugin to version 1.1.4 or later, and ensure that all users with import capabilities are properly restricted.