The Broken Link Checker WordPress plugin before 1.11.20 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)

The Broken Link Checker plugin for WordPress is vulnerable to deserialization of untrusted input via the '$log_file' value in versions up to, and including 1.11.16. This makes it possible for authenticated attackers with administrative privileges and above to call files using a PHAR wrapper that will deserialize the data and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.

A reflected XSS vulnerability was found in includes/admin/table-printer.php in the broken-link-checker (aka Broken Link Checker) plugin 1.11.8 for WordPress. This allows unauthorized users to inject client-side JavaScript into an admin-only WordPress page via the wp-admin/tools.php?page=view-broken-links s_filter parameter in a search action.

The broken-link-checker plugin through 1.11.8 for WordPress (aka Broken Link Checker) is susceptible to Reflected XSS due to improper encoding and insertion of an HTTP GET parameter into HTML. The filter function on the page listing all detected broken links can be exploited by providing an XSS payload in the s_filter GET parameter in a filter_id=search request. NOTE: this is an end-of-life product.

Cross-site scripting (XSS) vulnerability exists in the Wordpress admin panel when the Broken Link Checker plugin before 1.10.9 is installed.