CVE-2025-6921: The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (R

The huggingface/transformers library before version 4.53.0 has a vulnerability where malicious regular expressions (patterns used to match text) in certain settings can cause ReDoS (regular expression denial of service, a type of attack that makes a system use 100% CPU and become unresponsive). An attacker who can control these regex patterns in the AdamWeightDecay optimizer (a tool that helps train machine learning models) can make the system hang and stop working.