A flaw was discovered in postgresql versions 9.4.x before 9.4.24, 9.5.x before 9.5.19, 9.6.x before 9.6.15, 10.x before 10.10 and 11.x before 11.5 where arbitrary SQL statements can be executed given a suitable SECURITY DEFINER function. An attacker, with EXECUTE permission on the function, can execute arbitrary SQL as the owner of the function.

A vulnerability was found in PostgreSQL versions 11.x up to excluding 11.3, 10.x up to excluding 10.8, 9.6.x up to, excluding 9.6.13, 9.5.x up to, excluding 9.5.17. PostgreSQL maintains column statistics for tables. Certain statistics, such as histograms and lists of most common values, contain values taken from the column. PostgreSQL does not evaluate row security policies before consulting those statistics during query planning; an attacker can exploit this to read the most common values of certain columns. Affected columns are those for which the attacker has SELECT privilege and for which, in an ordinary query, row-level security prunes the set of rows visible to the attacker.

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.

In PostgreSQL 9.3 through 11.2, the "COPY TO/FROM PROGRAM" function allows superusers and users in the 'pg_execute_server_program' group to execute arbitrary code in the context of the database's operating system user. This functionality is enabled by default and can be abused to run arbitrary operating system commands on Windows, Linux, and macOS. NOTE: Third parties claim/state this is not an issue because PostgreSQL functionality for ‘COPY TO/FROM PROGRAM’ is acting as intended. References state that in PostgreSQL, a superuser can execute commands as the server user without using the ‘COPY FROM PROGRAM’.

postgresql before versions 11.1, 10.6 is vulnerable to a to SQL injection in pg_upgrade and pg_dump via CREATE TRIGGER ... REFERENCING. Using a purpose-crafted trigger definition, an attacker can cause arbitrary SQL statements to run, with superuser privileges.

It was discovered that PostgreSQL versions before 10.5, 9.6.10, 9.5.14, 9.4.19, and 9.3.24 failed to properly check authorization on certain statements involved with "INSERT ... ON CONFLICT DO UPDATE". An attacker with "CREATE TABLE" privileges could exploit this to read arbitrary bytes server memory. If the attacker also had certain "INSERT" and limited "UPDATE" privileges to a particular table, they could exploit this to update other columns in the same table.

A vulnerability was found in libpq, the default PostgreSQL client library where libpq failed to properly reset its internal state between connections. If an affected version of libpq was used with "host" or "hostaddr" connection parameters from untrusted input, attackers could bypass client-side connection security features, obtain access to higher privileged connections or potentially cause other impact through SQL injection, by causing the PQescape() functions to malfunction. Postgresql versions before 10.5, 9.6.10, 9.5.14, 9.4.19, and 9.3.24 are affected.

postgresql before versions 10.4, 9.6.9 is vulnerable in the adminpack extension, the pg_catalog.pg_logfile_rotate() function doesn't follow the same ACLs than pg_rorate_logfile. If the adminpack is added to a database, an attacker able to connect to it could exploit this to force log rotation.