GHSA-4C8J-MGM4-QQVP Remark42: Cross-Site Scripting (XSS) on /api/v1/img via content-type spoofing

Summary The remark42 image proxy fetches an arbitrary remote URL and re-serves the response from remark42's own origin. The download path decides whether the fetched resource is an image by looking only at the Content-Type header the remote server claims — it never inspects the actual bytes. The...