phpMyFAQ before 4.1.7, when configured to use PostgreSQL via the native pgsql PHP extension,...

phpMyFAQ before 4.1.7, when configured to use PostgreSQL via the native pgsql PHP extension, declares an incorrect LIKE ESCAPE character ('=') in the Search/Database/Pgsql.php backend while escapeLikeWildcards() escapes user input with the '|' prefix. As a result, wildcard escaping is a no-op and user-supplied % and _ characters remain active LIKE wildcards. An unauthenticated attacker can submit such characters in the public FAQ search form to force maximally broad pattern matches and expensive sequential scans, resulting in a denial of service. The PDO PostgreSQL backend is not affected, and quotes remain escaped so this does not enable quote-breaking SQL injection or data exfiltration.