Because the second argument is not a valid XPath, the database throws an error: XPATH syntax error: '~[md5_hash_here]' .

: This attempts to break out of the existing SQL string literal and uses a comment ( /**/ ) to bypass simple web application firewalls (WAFs) that might block standard spaces. extractvalue(1, concat(char(126), md5(1585491758))) : extractvalue() is a MySQL function for XML. char(126) is the tilde character ( ~ ).

: If the website displays this error message, the attacker confirms the site is vulnerable and can then proceed to extract sensitive data like usernames, passwords, or database schemas. Security Recommendation