Koha's reports/bor_issues_top.pl builds dynamic SQL in sub calculate by concatenating several user-controlled request parameters directly into the query string. The Criteria parameter is only normalized by a table-name prefix and is never whitelisted, landing verbatim in identifier positions (SELECT DISTINCTROW, GROUP BY, ORDER BY); Filter values are concatenated raw into single-quoted LIKE, BETWEEN, and comparison fragments, and the Limit parameter is appended raw to a LIMIT clause. An authenticated staff user holding the reports module permission can inject arbitrary SQL and read any table reachable by the Koha database user, including borrowers (password hashes, two-factor secrets, personal data), api_keys, and sessions.