CVE-2021-28363

MEDIUM
6.5
CVSS Score
Published: March 15, 2021 at 12:00 AM UTC
Updated: October 14, 2026 at 12:17 PM UTC
3 products affected across 3 vendorsFedoraPeopleSoft Enterprise PeopleToolsURLLIB3

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Severity
MEDIUM6.5
Exploit prediction
EPSS 2%

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.26.0 ≤ v < 1.26.4
Affected range stops below 1.26.4, so it looks safe — our inference, not a vendor statement

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-295

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