Comment 7 for bug 1324564

I guess #1304004 is marked private as it relates to a security package.

Good news is that I found a workaround by downgrading to libcurl3-gnutls_7.35.0-1ubuntu1. So far Transmission is stable with it even under high load.
Bad news is that this particular version has a couple of nasty security bugs and that you have to be extremely careful if downgrading, as this library is shared with many other applications and that you may be exposed.

I will mark this bug as affecting libcurl3-gnutls and see what its maintainer thinks. My guess is that the security fixes recently applied somehow break Transmission.