Source : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/9.4_release_notes/new-features#new-features-kernel

A new environment variable in Python to control parsing of email addresses

To mitigate CVE-2023-27043, a backward incompatible change to ensure stricter parsing of email addresses was introduced in Python 3.

This update introduces a new PYTHON_EMAIL_DISABLE_STRICT_ADDR_PARSING environment variable. When you set this variable to true, the previous, less strict parsing behavior is the default for the entire system:

export PYTHON_EMAIL_DISABLE_STRICT_ADDR_PARSING=true

However, individual calls to the affected functions can still enable stricter behavior.

You can achieve the same result by creating the /etc/python/email.cfg configuration file with the following content:

/etc/python/email.cfg

[email_addr_parsing]
PYTHON_EMAIL_DISABLE_STRICT_ADDR_PARSING = true

For more information, see the Knowledgebase article Mitigation of CVE-2023-27043 introducing stricter parsing of email addresses in Python.