changedetection.io: Reflected XSS in RSS Tag Error Response

changedetection.io is a free open source web page change detection tool. Prior to version 0.54.4, there is a reflected cross-site scripting (XSS) vulnerability identified in the /rss/tag/ endpoint of changedetection.io. The tag_uuid path parameter is reflected directly in the HTTP response body without HTML escaping. Since Flask returns text/html by default for plain string responses, the browser parses and executes injected JavaScript. This issue has been patched in version 0.54.4.