USN-4972-1: PostgreSQL vulnerabilities

Tom Lane discovered that PostgreSQL incorrect handled certain array subscripting calculations. An authenticated attacker could possibly use this issue to overwrite server memory and escalate privileges. (CVE-2021-32027) Andres Freund discovered that PostgreSQL incorrect handled certain INSERT ... ON CONFLICT ... DO UPDATE commands. A remote attacker could possibly use this issue to read server memory and obtain sensitive information. (CVE-2021-32028) Tom Lane discovered that PostgreSQL incorrect handled certain UPDATE ... RETURNING commands. A remote attacker could possibly use this issue to read server memory and obtain sensitive information. This issue only affected Ubuntu 20.04 LTS, Ubuntu 20.10, and Ubuntu 21.04. (CVE-2021-32029)