GHSA-g3pv-pj5f-3hfq

mechanize Regular Expression Denial of Service vulnerability

Source: GitHub Advisory Database (reviewed) High CVE-2021-32837

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	mechanize	< 0.4.6	0.4.6

Details

As written in the advisory (Markdown source, shown as plain text).

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.

References

External links from the advisory. They lead to third-party sites.

https://nvd.nist.gov/vuln/detail/CVE-2021-32837 advisory
https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6 web
https://github.com/pypa/advisory-database/tree/main/vulns/mechanize/PYSEC-2023-25.yaml web
https://github.com/python-mechanize/mechanize package
https://github.com/python-mechanize/mechanize/blob/3acb1836f3fd8edc5a758a417dd46b53832ae3b5/mechanize/_urllib2_fork.py#L878-L879 web
https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6 web
https://lists.debian.org/debian-lts-announce/2023/06/msg00022.html web
https://lists.debian.org/debian-lts-announce/2025/12/msg00028.html web
https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize advisory