Ubuntu Security Notice 4973-2 - 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. 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. Various other issues were also addressed.
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