resumable.php (aka PHP backend for resumable.js) 0.1.4 before 3c6dbf5 allows arbitrary file upload anywhere in the filesystem via ../ in multipart/form-data content to upload.php. (File overwrite hasn't been possible with the code available in GitHub in recent years, however.)
https://github.com/dilab/resumable.php/pull/39/commits/d3552efd403e2d87407934477eee642836cab3b4
https://github.com/dilab/resumable.php/pull/39/commits/408f54dff10e48befa44d417933787232a64304b
https://github.com/dilab/resumable.php/pull/27/commits/3e3c94d0302bb399a7611b4738a5a4dd0832a926
https://github.com/dilab/resumable.php/issues/34
https://github.com/dilab/resumable.php/commit/3c6dbf5170b01cbb712013c7d0a83f5aac45653b