Flask file upload in 32-bit Debian Stretch

If you upgrade to 32-bit Debian stretch and suddenly file uploads start failing in your Flask applications, this is caused by a bug in mod_wsgi. Just grab a never package from debian testing (4.5.17 seems to be ok).

The bug causes the application to produce “Bad Request” errors. I will affect anything based on Werkzeug and probably all mod_wsgi based applications. The bug is fixed in mod_wsgi commit 9192fd36620 and the patch is not in Stretch as of today.