A flaw was found in PostgreSQL versions before 13.1, before 12.5, before 11.10, before 10.15, before 9.6.20 and before 9.5.24. An attacker having permission to create non-temporary objects in at least one schema can execute arbitrary SQL functions under the identity of a superuser. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
https://bugzilla.redhat.com/show_bug.cgi?id=1894425
https://lists.debian.org/debian-lts-announce/2020/12/msg00005.html
https://security.gentoo.org/glsa/202012-07