{"id":"CVE-2021-32837","aliases":["GHSA-g3pv-pj5f-3hfq","PYSEC-2023-25"],"url":"https://o3.security/vulnerability/CVE-2021-32837","summary":"mechanize Regular Expression Denial of Service vulnerability","details":"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.","published":"2023-01-17T22:15:10.533Z","modified":"2026-07-09T00:36:25.743486Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":2,"affectedPackages":[{"ecosystem":"PyPI","name":"mechanize","fixedVersion":"0.4.6"}],"fix":{"url":"https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6","label":"python-mechanize/mechanize@dd05334"},"references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2023/06/msg00022.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/12/msg00028.html"},{"type":"ADVISORY","url":"https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6"},{"type":"FIX","url":"https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6"},{"type":"EVIDENCE","url":"https://github.com/python-mechanize/mechanize/blob/3acb1836f3fd8edc5a758a417dd46b53832ae3b5/mechanize/_urllib2_fork.py#L878-L879"},{"type":"EVIDENCE","url":"https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32837"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/mechanize/PYSEC-2023-25.yaml"},{"type":"PACKAGE","url":"https://github.com/python-mechanize/mechanize"},{"type":"ADVISORY","url":"https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T00:36:25.743486Z"}}