VDB
ALPINE-CVE-2021-28363
ALPINE-CVE-2021-28363
PUBLISHED
CVSS 6.5 MEDIUM
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.
Risk Scores
CVSS v3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Alpine:v3.14 | py3-urllib3 | 1.26.3-r0, 0, 1.21.1-r0 |
| Alpine:v3.16 | py3-urllib3 | 1.21.1-r0, 1.24.1-r0, 1.24.1-r1 |
| Alpine:v3.18 | py3-urllib3 | 1.25.8-r0, 0, 1.18-r0 |
| Alpine:v3.15 | py3-urllib3 | 1.26.3-r0, 1.26.2-r1, 1.26.2-r0 |
| Alpine:v3.21 | py3-urllib3 | 0, 1.22-r0, 1.24.1-r0 |
| Alpine:v3.22 | py3-urllib3 | 1.25.10-r0, 0, 1.26.3-r0 |
| Alpine:v3.23 | py3-urllib3 | 1.26.3-r0, 0, 1.21.1-r0 |
| Alpine:v3.19 | py3-urllib3 | 1.24.1-r1, 1.18-r0, 1.21.1-r0 |
| Alpine:v3.17 | py3-urllib3 | 0, 1.18-r0, 1.24.1-r0 |
| Alpine:v3.20 | py3-urllib3 | 1.26.3-r0, 1.18-r0, 1.22-r0 |
Timeline
- Mar 15, 2021 CVE Published
- Dec 3, 2025 CVE Updated
- Apr 30, 2026 Distribution Patch