Description
In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This (in some situations) allows attackers to bypass access control that is based on IP addresses.
Published: 2021-05-06
Score: 9.8 Critical
EPSS: 2.0% Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-3980-1 python3.9 security update
EUVD EUVD EUVD-2021-16395 In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This (in some situations) allows attackers to bypass access control that is based on IP addresses.
Ubuntu USN Ubuntu USN USN-4973-1 Python vulnerability
Ubuntu USN Ubuntu USN USN-4973-2 Python vulnerability
Ubuntu USN Ubuntu USN USN-6891-1 Python vulnerabilities
History

Mon, 03 Nov 2025 22:30:00 +0000

Type Values Removed Values Added
References

Subscriptions

Oracle Communications Cloud Native Core Automated Test Suite Communications Cloud Native Core Binding Support Function Communications Cloud Native Core Network Slice Selection Function Graalvm Zfs Storage Appliance Kit
Python Python
Redhat Enterprise Linux Rhel Software Collections
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2025-11-03T21:44:43.122Z

Reserved: 2021-04-01T00:00:00.000Z

Link: CVE-2021-29921

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-05-06T13:15:12.573

Modified: 2025-11-03T22:15:48.057

Link: CVE-2021-29921

cve-icon Redhat

Severity : Moderate

Publid Date: 2021-04-30T00:00:00Z

Links: CVE-2021-29921 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses