mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.
https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize/
https://lists.debian.org/debian-lts-announce/2023/06/msg00022.html
https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6
https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6