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Vulnerability · Published Mar 15, 2021 · Assigned by mitre

CVE-2021-28363

Medium 6.5

In plain English

A medium-severity security flaw in the py3-urllib3 package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.2% (higher than 82% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)6.5Medium
Exploit odds (30 days)2.2%top 17.7% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20py3-urllib31.26.4-r0ALPINE-CVE-2021-28363
Alpine:v3.21py3-urllib31.26.4-r0ALPINE-CVE-2021-28363
Alpine:v3.22py3-urllib31.26.4-r0ALPINE-CVE-2021-28363
Alpine:v3.23py3-urllib31.26.4-r0ALPINE-CVE-2021-28363
Alpine:v3.24py3-urllib31.26.4-r0ALPINE-CVE-2021-28363
Debian:12python-urllib31.26.4-1DEBIAN-CVE-2021-28363
Debian:13python-urllib31.26.4-1DEBIAN-CVE-2021-28363
Debian:14python-urllib31.26.4-1DEBIAN-CVE-2021-28363
PyPIurllib31.26.4PYSEC-2021-59
PyPIurllib31.26.4GHSA-5phf-pp7p-vc2r

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

References