In phpMyFAQ before version 4.1.7 and including 4.2.0-alpha, when using the native pgsql PHP extension for PostgreSQL, the declared LIKE ESCAPE character ('=') in the Search/Database/Pgsql.php backend is incorrect. The escapeLikeWildcards() function escapes user input with a '|' prefix, causing wildcard escaping to be ineffective. Consequently, user-supplied '%' and '_' characters remain active as LIKE wildcards. An unauthenticated attacker can exploit this by submitting such characters in the public FAQ search form, triggering broad pattern matches and expensive sequential scans that result in denial of service. The PDO PostgreSQL backend is not affected, and quotes remain escaped, so this vulnerability does not lead to SQL injection or data exfiltration.

An unauthenticated attacker can cause denial of service by submitting specially crafted input containing wildcard characters in the public FAQ search form. This forces broad pattern matches and resource-intensive sequential scans on the database, potentially degrading or disrupting service availability. There is no risk of SQL injection or data leakage from this vulnerability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider disabling the native pgsql PHP extension backend or restricting access to the public FAQ search form to mitigate denial of service risk. The PDO PostgreSQL backend is not affected and can be used as an alternative.