CVE-2021-32837
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 28.9%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 28.87% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-1333
- Affected
- mechanize project/mechanize
- Source
- security-advisories@github.com
EPSS 28.9% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/python-mechanize/mechanize/blob/3acb1836f3fd8edc5a758a417dd46b53832ae3b5/mechanize/_urllib2_fork.py#L878-L879Exploit, Third Party Advisory
- https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6Patch, Third Party Advisory
- https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/06/msg00022.html
- https://securitylab.github.com/advisories/GHSL-2021-108-python-mechanize-mechanize/Exploit, Third Party Advisory
- https://github.com/python-mechanize/mechanize/blob/3acb1836f3fd8edc5a758a417dd46b53832ae3b5/mechanize/_urllib2_fork.py#L878-L879Exploit, Third Party Advisory
- https://github.com/python-mechanize/mechanize/commit/dd05334448e9f39814bab044d2eaa5ef69b410d6Patch, Third Party Advisory
- https://github.com/python-mechanize/mechanize/releases/tag/v0.4.6Third Party Advisory
- 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/Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.