CVE-2021-29921

9.8 CRITICAL
Published: May 06, 2021 Modified: November 03, 2025
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://bugs.python.org/issue36384
Source: cve@mitre.org
Issue Tracking Patch Vendor Advisory
https://docs.python.org/3/library/ipaddress.html
Source: cve@mitre.org
Vendor Advisory
https://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst
Source: cve@mitre.org
Third Party Advisory
https://github.com/python/cpython/pull/12577
Source: cve@mitre.org
Patch Third Party Advisory
https://github.com/python/cpython/pull/25099
Source: cve@mitre.org
Patch Third Party Advisory
https://github.com/sickcodes
Source: cve@mitre.org
Third Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-014.md
Source: cve@mitre.org
Exploit Third Party Advisory
https://python-security.readthedocs.io/vuln/ipaddress-ipv4-leading-zeros.html
Source: cve@mitre.org
Vendor Advisory
https://security.gentoo.org/glsa/202305-02
Source: cve@mitre.org
https://security.netapp.com/advisory/ntap-20210622-0003/
Source: cve@mitre.org
Third Party Advisory
https://sick.codes/sick-2021-014
Source: cve@mitre.org
Exploit Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html
Source: cve@mitre.org
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html
Source: cve@mitre.org
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: cve@mitre.org
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html
Source: cve@mitre.org
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: cve@mitre.org
Patch Third Party Advisory
https://bugs.python.org/issue36384
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Patch Vendor Advisory
https://docs.python.org/3/library/ipaddress.html
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://github.com/python/cpython/pull/12577
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://github.com/python/cpython/pull/25099
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://github.com/sickcodes
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-014.md
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
Source: af854a3a-2127-422b-91ae-364da2661108
https://python-security.readthedocs.io/vuln/ipaddress-ipv4-leading-zeros.html
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://security.gentoo.org/glsa/202305-02
Source: af854a3a-2127-422b-91ae-364da2661108
https://security.netapp.com/advisory/ntap-20210622-0003/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://sick.codes/sick-2021-014
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory

33 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
1.8%
82th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

oracle python