Avoid XSS when opening a broken image due to unescaped ServerError in proxy handler #1746
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… proxy handler Creating an RSS feed item with the inline description containing an `<img>` tag with a `srcset` attribute pointing to an invalid URL like `http:a<script>alert(1)</script>`, we can coerce the proxy handler into an error condition where the invalid URL is returned unescaped and in full. This results in JavaScript execution on the Miniflux instance as soon as the user is convinced to open the broken image.
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Creating an RSS feed item with the inline description containing an
<img>tag with asrcsetattribute pointing to an invalid URL likehttp:a<script>alert(1)</script>, we can coerce the proxy handler into an error condition where the invalid URL is returned unescaped and in full.This results in JavaScript execution on the Miniflux instance as soon as the user is convinced to open the broken image.
Do you follow the guidelines?