python39:3.9 security update

Python is an interpreted, interactive, object-oriented programming language,
which includes modules, classes, exceptions, very high level dynamic data types
and dynamic typing. Python supports interfaces to many system calls and
libraries, as well as to various windowing systems.

Security Fix(es):

* python: local privilege escalation via the multiprocessing forkserver start
method (CVE-2022-42919)

For more details about the security issue(s), including the impact, a CVSS
score, acknowledgments, and other related information, refer to the CVE page(s)
listed in the References section.

CVE-2022-42919
Python 3.9.x and 3.10.x through 3.10.8 on Linux allows local privilege
escalation in a non-default configuration. The Python multiprocessing library,
when used with the forkserver start method on Linux, allows pickles to be
deserialized from any user in the same machine local network namespace, which in
many system configurations means any user on the same machine. Pickles can
execute arbitrary code. Thus, this allows for local user privilege escalation to
the user that any forkserver process is running as. Setting
multiprocessing.util.abstract_sockets_supported to False is a workaround. The
forkserver start method for multiprocessing is not the default start method.
This issue is Linux specific because only Linux supports abstract namespace
sockets. CPython before 3.9 does not make use of Linux abstract namespace
sockets by default. Support for users manually specifying an abstract namespace
socket was added as a bugfix in 3.7.8 and 3.8.4, but users would need to make
specific uncommon API calls in order to do that in CPython before 3.9.

Modularity name: python39
Stream name: 3.9