PostgreSQL versions 10.x before 10.9 and versions 11.x before 11.4 are vulnerable to a stack-based buffer overflow

PostgreSQL versions 10.x before 10.9 and versions 11.x before 11.4 are vulnerable to a stack-based buffer overflow. Any authenticated user can overflow a stack-based buffer by changing the user's own password to a purpose-crafted value. This often suffices to execute arbitrary code as the PostgreSQL operating system account.