CVE-2021-28363

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.

How to fix CVE-2021-28363

To remediate CVE-2021-28363, upgrade the affected package to a fixed version below.

• —upgrade to 1.26.4-r0 or later
• —upgrade to 1.26.4-1 or later
• —upgrade to 1.26.4 or later
• —upgrade to 8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0 or later

Is CVE-2021-28363 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (4)

• from 0, < 1.26.4-r0
• from 0, < 1.26.4-1
• >= 1.26.0, < 1.26.4
• from 0, < 8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0 | >= 1.26.0, < 1.26.4

CVSS scores

References (19)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-28363
• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2021-28363
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-28363
• PATCHgithub.com/urllib3/urllib3
• PATCH