XSS when attaching a file to an issue

Hi,

I found a persistent XSS vulnerability when attaching a file to an issue.
The steps to reproduce are the following :

• Attach a file to an issue. Its name must contain "<script>alert('XSS')</script>". I used a python script to do that.

• Browse to the issue and open the ALL tab under activity. A popup should appear.

See the attachment for the result.