Ubuntu Security Notice 4754-4 – USN-4754-1 fixed vulnerabilities in Python. Because of a regression, a subsequent update removed the fix for CVE-2021-3177. This update reinstates the security fix for CVE-2021-3177. It was discovered that Python incorrectly handled certain inputs. An attacker could possibly use this issue to execute arbitrary code or cause a denial of service. Various other issues were also addressed.