The Columns by BestWebSoft plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'id' shortcode attribute of the [printclmns] shortcode in all versions up to and including 1.0.3. This is due to insufficient input sanitization and output escaping on the 'id' attribute. The shortcode receives the 'id' parameter via shortcodeatts() at line 596 and directly embeds it into HTML output at line 731 (in a div id attribute) and into inline CSS at lines 672-729 without any escaping or sanitization. While the SQL query uses %d to cast the value to an integer for database lookup, the original unsanitized string value of $id is still used in the HTML/CSS output. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The attack requires that at least one column exists in the plugin (created by an admin), as the SQL query must return results for the output branch to be reached.