SolidInvoice is an open-source invoicing platform. Prior to version 2.3.17, the company logo upload feature accepts any file type without validation. An authenticated administrator can upload an SVG file containing embedded JavaScript. This script is base64-encoded and injected unescaped into every page of the application, causing stored cross-site scripting (XSS) that executes in every authenticated user's browser. This issue has been patched in version 2.3.17.