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.
The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data.