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. If a client application that creates additional database connections only reuses the basic connection parameters while dropping security-relevant parameters, an opportunity for a man-in-the-middle attack, or the ability to observe clear-text transmissions, could exist. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

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.

It was found that some PostgreSQL extensions did not use search_path safely in their installation script. An attacker with sufficient privileges could use this flaw to trick an administrator into executing a specially crafted script, during the installation or update of such extension. This affects PostgreSQL versions before 12.4, before 11.9, before 10.14, before 9.6.19, and before 9.5.23.

The snprintf implementation in PostgreSQL before 9.0.20, 9.1.x before 9.1.16, 9.2.x before 9.2.11, 9.3.x before 9.3.7, and 9.4.x before 9.4.2 does not properly handle system-call errors, which allows attackers to obtain sensitive information or have other unspecified impact via unknown vectors, as demonstrated by an out-of-memory error.

contrib/pgcrypto in PostgreSQL before 9.0.20, 9.1.x before 9.1.16, 9.2.x before 9.2.11, 9.3.x before 9.3.7, and 9.4.x before 9.4.2 uses different error responses when an incorrect key is used, which makes it easier for attackers to obtain the key via a brute force attack.

The pg_ctlcluster script in postgresql-common in versions prior to 210 didn't drop privileges when creating socket/statistics temporary directories, which could result in local privilege escalation.

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.

INSERT ... ON CONFLICT DO UPDATE commands in PostgreSQL 10.x before 10.1, 9.6.x before 9.6.6, and 9.5.x before 9.5.10 disclose table contents that the invoker lacks privilege to read. These exploits affect only tables where the attacker lacks full read access but has both INSERT and UPDATE privileges. Exploits bypass row level security policies and lack of SELECT privilege.

PostgreSQL versions before 9.4.13, 9.5.8 and 9.6.4 are vulnerable to authorization flaw allowing remote authenticated attackers with no privileges on a large object to overwrite the entire contents of the object, resulting in a denial of service.