CVE-2021-28363
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.
- CVSS 3.1
- 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - EPSS
- 2.2% chance of exploitation in the next 30 days; higher than 82% of CVEs (scores of 2026-10-25)
- CWE
- CWE-295
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fedoraproject:fedora
- oracle:peoplesoft_enterprise_peopletools
- python:urllib3
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-5phf-pp7p-vc2r | PyPI | urllib3 | >=1.26.0 <1.26.4 | 1.26.4 |
| PYSEC-2021-59 | PyPI | urllib3 | >=1.26.0 <1.26.4 | 1.26.4 |
References
- https://github.com/urllib3/urllib3/commit/8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0
- https://github.com/urllib3/urllib3/commits/main
- https://github.com/urllib3/urllib3/security/advisories/GHSA-5phf-pp7p-vc2r
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S65ZQVZ2ODGB52IC7VJDBUK4M5INCXL/
- https://pypi.org/project/urllib3/1.26.4/