A HTML injection vulnerability exists in the file upload functionality of Cacti <= 1.2.29. When a file with an invalid format is uploaded, the application reflects the submitted filename back into an error popup without proper sanitization. As a result, attackers can inject arbitrary HTML elements (e.g., <h1>, <b>, <svg>) into the rendered page.
https://github.com/Cacti/cacti
https://gist.github.com/BEND0US/49d76897a5bb676d8c3f51425553cc32