Ubuntu 20.04 LTS : Python vulnerability (USN-4973-2)

critical Nessus Plugin ID 153852
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The remote Ubuntu host is missing a security update.


The remote Ubuntu 20.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-4973-2 advisory.

- 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. (CVE-2021-29921)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Update the affected packages.

See Also


Plugin Details

Severity: Critical

ID: 153852

File Name: ubuntu_USN-4973-2.nasl

Version: 1.2

Type: local

Agent: unix

Published: 10/4/2021

Updated: 10/4/2021

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2021-29921


Risk Factor: High

Score: 7.4


Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:idle-python3.8, p-cpe:/a:canonical:ubuntu_linux:libpython3.8, p-cpe:/a:canonical:ubuntu_linux:libpython3.8-dev, p-cpe:/a:canonical:ubuntu_linux:libpython3.8-minimal, p-cpe:/a:canonical:ubuntu_linux:libpython3.8-stdlib, p-cpe:/a:canonical:ubuntu_linux:libpython3.8-testsuite, p-cpe:/a:canonical:ubuntu_linux:python3.8, p-cpe:/a:canonical:ubuntu_linux:python3.8-dev, p-cpe:/a:canonical:ubuntu_linux:python3.8-examples, p-cpe:/a:canonical:ubuntu_linux:python3.8-full, p-cpe:/a:canonical:ubuntu_linux:python3.8-minimal, p-cpe:/a:canonical:ubuntu_linux:python3.8-venv

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 10/4/2021

Vulnerability Publication Date: 5/6/2021

Reference Information

CVE: CVE-2021-29921

USN: 4973-2

IAVA: 2021-A-0263