CVE-2021-28363

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2021-28363
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-03-15 18:15:19 UTC
Updated2026-10-14 12:17:11 UTC
DescriptionThe 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 And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Problem Types: CWE-295 | n/a

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
2.0[email protected]Primary6.4AV:N/AC:L/Au:N/C:P/I:P/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
None

AV:N/AC:L/Au:N/C:P/I:P/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Fedoraproject Fedora 34 All All All
Application Oracle Peoplesoft Enterprise Peopletools 8.59 All All All
Application Python Urllib3 All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na N/a affected n/a Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.0 V3.1.5 custom Not specified

References

ReferenceSourceLinkTags
cert-portal.siemens.com/productcert/html/ssa-398330.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
Oracle Critical Patch Update Advisory - October 2021 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
Commits · urllib3/urllib3 · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
security.netapp.com/advisory/ntap-20240621-0007 af854a3a-2127-422b-91ae-364da2661108 security.netapp.com
Using default SSLContext for HTTPS requests in an HTTPS proxy doesn't verify certificate hostname for proxy connection · Advisory · urllib3/urllib3 · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Mitigation, Third Party Advisory
[SECURITY] Fedora 34 Update: python-pip-21.0.1-3.fc34 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
urllib3: Multiple vulnerabilities (GLSA 202107-36) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org Third Party Advisory
Merge pull request from GHSA-5phf-pp7p-vc2r · urllib3/urllib3@8d65ea1 · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
Python, PyPy3: Multiple Vulnerabilities (GLSA 202305-02) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org
urllib3 · PyPI af854a3a-2127-422b-91ae-364da2661108 pypi.org Third Party Advisory
[SECURITY] Fedora 34 Update: python-pip-21.0.1-3.fc34 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 179631 Debian Security Update for python-urllib3 (CVE-2021-28363)
  • 281095 Fedora Security Update for python (FEDORA-2021-3f378dda90)
  • 352387 Amazon Linux Security Advisory for python-pip: ALAS2-2021-1667
  • 353121 Amazon Linux Security Advisory for python-pip : ALAS2-2022-1742
  • 375970 Oracle PeopleSoft Enterprise PeopleTools Product Multiple Vulnerabilities (CPUOCT2021)
  • 501771 Alpine Linux Security Update for py3-urllib3
  • 504335 Alpine Linux Security Update for py3-urllib3
  • 710032 Gentoo Linux urllib3 Multiple vulnerabilities (GLSA 202107-36)
  • 710714 Gentoo Linux Python, PyPy3 Multiple Vulnerabilities (GLSA 202305-02)
  • 980343 Python (pip) Security Update for urllib3 (GHSA-5phf-pp7p-vc2r)

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report