VULNERABILITY INTELLIGENCE
CVE-2021-28363
CVSS score6.5 MEDIUM
EPSS probability2.17%
CISA KEVNot currently listed
Published2021-03-15
Last modified2026-10-14
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Description
The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. The initial connection to the HTTPS proxy (if an SSLContext isn't given via proxy_config) doesn't verify the hostname of the certificate. This means certificates for different servers that still validate properly with the default urllib3 SSLContext will be silently accepted.
Weakness classification
- nvd@nist.gov: CWE-295
Primary references
- cve@mitre.org — Patch, Third Party Advisory
- cve@mitre.org — Patch, Third Party Advisory
- cve@mitre.org — Mitigation, Third Party Advisory
- cve@mitre.org
- cve@mitre.org — Third Party Advisory
- cve@mitre.org — Third Party Advisory
- cve@mitre.org
- cve@mitre.org
- cve@mitre.org — Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Mitigation, Third Party Advisory