A vulnerability in huggingface/transformers versions <=5.8.0.dev0 allows an attacker to perform arbitrary file writes via path traversal. The issue resides in the "save_pretrained()" methods of "PreTrainedTokenizerBase" and "ProcessorMixin", where keys from the "chat_template" dictionary are used directly as filenames without proper validation. An attacker can exploit this by publishing a malicious Hugging Face Hub repository with a crafted "tokenizer_config.json" file. When a victim downloads and saves the tokenizer or processor, the attacker-controlled keys can escape the intended save directory, enabling arbitrary file writes with attacker-controlled content. This vulnerability affects multiple processors inheriting from "ProcessorMixin", including Idefics, Florence, Gemma, Phi, and Qwen-VL.