postgresql-10 vulnerabilities

USN-6538-1 fixed several vulnerabilities in PostgreSQL. This update provides
the corresponding updates for Ubuntu 18.04 LTS.

Original advisory details:

Jingzhou Fu discovered that PostgreSQL incorrectly handled certain unknown
arguments in aggregate function calls. A remote attacker could possibly use
this issue to obtain sensitive information. (CVE-2023-5868)

Pedro Gallegos discovered that PostgreSQL incorrectly handled modifying
certain SQL array values. A remote attacker could use this issue to obtain
sensitive information, or possibly execute arbitrary code. (CVE-2023-5869)

Hemanth Sandrana and Mahendrakar Srinivasarao discovered that PostgreSQL
allowed the pg_signal_backend role to signal certain superuser processes,
contrary to expectations. (CVE-2023-5870)