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
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | mechanize | < 0.4.6 | 0.4.6 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2021-32837
- https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6
- https://github.com/pypa/advisory-database/tree/main/vulns/mechanize/PYSEC-2023-25.yaml
- https://github.com/python-mechanize/mechanize
- https://github.com/python-mechanize/mechanize/blob/3acb1836f3fd8edc5a758a417dd46b53832ae3b5/mechanize/_urllib2_fork.py#L878-L879
- https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6
- https://lists.debian.org/debian-lts-announce/2023/06/msg00022.html
- https://lists.debian.org/debian-lts-announce/2025/12/msg00028.html
- https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize
- https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize/
- https://github.com/advisories/GHSA-g3pv-pj5f-3hfq
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1333- Platform
- Python (PyPI)
- Package
mechanize- Disclosed
- 17.01.2023
- Updated
- 11.10.2026 12:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-g3pv-pj5f-3hfq - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2023-25 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: mechanize
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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