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USN-5199-1: Python vulnerabilities

17 December 2021

Python could be made to crash if it receives specially crafted input from a malicious server.



  • python3.6 - An interactive high-level object-oriented language


It was discovered that the urllib.request.AbstractBasicAuthHandler class
in Python contains regex with a quadratic worst-case time complexity.
Specially crafted traffic from a malicious HTTP server could cause a regular
expression denial of service (ReDoS) condition for a client.

It was discovered that the Python urllib http client could enter into an infinite
loop when incorrectly handling certain server responses (100 Continue response).
Specially crafted traffic from a malicious HTTP server could cause a denial of
service (DoS) condition for a client.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 18.04

In general, a standard system update will make all the necessary changes.

Related notices

  • USN-5083-1: idle-python3.4, idle-python3.5, libpython3.4-minimal, libpython3.5-dev, python3.5-venv, python3.4-doc, python3.4-minimal, python3.5, libpython3.5-testsuite, python3.4-dev, libpython3.4-stdlib, python3.5-minimal, python3.4-venv, libpython3.5, python3.5-examples, libpython3.4, libpython3.4-testsuite, python3.4, libpython3.4-dev, python3.5-dev, python3.4-examples, libpython3.5-minimal, libpython3.5-stdlib, python3.5-doc
  • USN-5200-1: python3.7-dev, python3.8-examples, libpython3.8, python3.7, python3.7-venv, libpython3.7-stdlib, libpython3.7-testsuite, python3.8-dev, libpython3.7-dev, libpython3.7-minimal, idle-python3.7, python3.7-doc, libpython3.8-stdlib, idle-python3.8, python3.8-venv, libpython3.8-testsuite, python3.7-minimal, libpython3.8-minimal, python3.8-minimal, libpython3.8-dev, libpython3.7, python3.7-examples, python3.8
  • USN-5201-1: python3.8-examples, python3.9-full, libpython3.8, libpython3.9-testsuite, libpython3.9, libpython3.9-minimal, python3.8-dev, idle-python3.9, python3.9-doc, python3.9-examples, libpython3.8-stdlib, libpython3.9-dev, idle-python3.8, python3.9-dev, python3.8-venv, libpython3.8-testsuite, libpython3.8-minimal, python3.8-minimal, python3.8-full, python3.8-doc, libpython3.8-dev, libpython3.9-stdlib, python3.9-minimal, python3.8, python3.9, python3.9-venv