=========================================================================Ubuntu Security Notice USN-5200-1
December 17, 2021
python3.7, python3.8 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS
Summary:
Python could be made to crash if it receives specially crafted input
from a malicious server.
Software Description:
- python3.7: An interactive high-level object-oriented language
- python3.8: An interactive high-level object-oriented language
Details:
It was discovered that the urllib.request.AbstractBasicAuthHandler class
in Python contains regex allowing for catastrophic backtracking. Specially
crafted traffic from a malicious HTTP server could cause a regular
expression
denial of service (ReDoS) condition for a client.
(CVE-2020-8492)
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.
(CVE-2021-3733)
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.
(CVE-2021-3737)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.04 LTS:
libpython3.7-stdlib 3.7.5-2ubuntu1~18.04.2
libpython3.8-stdlib 3.8.0-3ubuntu1~18.04.2
python3.7 3.7.5-2ubuntu1~18.04.2
python3.7-minimal 3.7.5-2ubuntu1~18.04.2
python3.8 3.8.0-3ubuntu1~18.04.2
python3.8-minimal 3.8.0-3ubuntu1~18.04.2
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-5200-1
CVE-2020-8492, CVE-2021-3733, CVE-2021-3737
Package Information:
https://launchpad.net/ubuntu/+source/python3.7/3.7.5-2ubuntu1~18.04.2
https://launchpad.net/ubuntu/+source/python3.8/3.8.0-3ubuntu1~18.04.2
