Moderate: postgresql15 security update (Amazon Linux 2023)

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2023-39418: A vulnerability was found in PostgreSQL with the use of the MERGE command, which fails to test new rows against row security policies defined for UPDATE and SELECT. If UPDATE and SELECT policies forbid some rows that INSERT policies do not forbid, a user could store such rows. CVE-2023-2455: While CVE-2016-2193 fixed most interaction between row security and user ID changes, it missed a scenario involving function inlining. This leads to potentially incorrect policies being applied in cases where role-specific policies are used and a given query is planned under one role and then executed under other roles. This scenario can happen under security definer functions or when a common user and query is planned initially and then re-used across multiple SET ROLEs. Applying an incorrect policy may permit a user to complete otherwise-forbidden reads and modifications. This affects only databases that have used CREATE POLICY to define a row security policy. CVE-2022-41862: In PostgreSQL, a modified, unauthenticated server can send an unterminated string during the establishment of Kerberos transport encryption. In certain conditions a server can cause a libpq client to over-read and report an error message containing uninitialized bytes.