USN-4973-1 fixed this vulnerability previously, but it was re-introduced in python3.8 in focal because of the SRU in LP: #1928057. This update fixes the problem.
Original advisory details:
It was discovered that the Python stdlib ipaddress API incorrectly handled octal strings. A remote attacker could possibly use this issue to perform a wide variety of attacks, including bypassing certain access restrictions.
3.8.10-0ubuntu1~20.04.1