m1k1o/blog is a lightweight self-hosted facebook-styled PHP blog. Errors from functions `imagecreatefrom*` and `image*` have not been checked properly. Although PHP issued warnings and the upload function returned `false`, the original file (that could contain a malicious payload) was kept on the disk. Users are advised to upgrade as soon as possible. There are no known workarounds for this issue.
upload.php in tianchoy/blog through 2017-09-12 allows unrestricted file upload and PHP code execution by using the image/jpeg, image/pjpeg, image/png, or image/gif content type for a .php file.