Pdfminer.six is a community maintained fork of the original PDFMiner, a tool for extracting information from PDF documents. Prior to version 20251107, pdfminer.six will execute arbitrary code from a malicious pickle file if provided with a malicious PDF file. The `CMapDB._load_data()` function in pdfminer.six uses `pickle.loads()` to deserialize pickle files. These pickle files are supposed to be part of the pdfminer.six distribution stored in the `cmap/` directory, but a malicious PDF can speci...