Ubuntu 18.04 LTS : Python vulnerabilities (USN-5200-1)

high Nessus Plugin ID 156171


The remote Ubuntu host is missing one or more security updates.


The remote Ubuntu 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5200-1 advisory.

- Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking. (CVE-2020-8492)

- There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

- A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop, consuming CPU time. The highest threat from this vulnerability is to system availability. (CVE-2021-3737)

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: High

ID: 156171

File Name: ubuntu_USN-5200-1.nasl

Version: 1.7

Type: local

Agent: unix

Published: 12/18/2021

Updated: 10/16/2023

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information


Risk Factor: Medium

Score: 4.4


Risk Factor: High

Base Score: 7.1

Temporal Score: 5.6

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2021-3737


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:idle-python3.7, p-cpe:/a:canonical:ubuntu_linux:idle-python3.8, p-cpe:/a:canonical:ubuntu_linux:libpython3.7, p-cpe:/a:canonical:ubuntu_linux:libpython3.7-dev, p-cpe:/a:canonical:ubuntu_linux:libpython3.7-minimal, p-cpe:/a:canonical:ubuntu_linux:libpython3.7-stdlib, p-cpe:/a:canonical:ubuntu_linux:libpython3.7-testsuite, 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:python3.7, p-cpe:/a:canonical:ubuntu_linux:python3.7-dev, p-cpe:/a:canonical:ubuntu_linux:python3.7-examples, p-cpe:/a:canonical:ubuntu_linux:python3.7-minimal, p-cpe:/a:canonical:ubuntu_linux:python3.7-venv, 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-minimal, p-cpe:/a:canonical:ubuntu_linux:python3.8-venv

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/17/2021

Vulnerability Publication Date: 1/30/2020

Reference Information

CVE: CVE-2020-8492, CVE-2021-3733, CVE-2021-3737

IAVA: 2020-A-0103-S, 2021-A-0497-S

USN: 5200-1