fetchmail -- chosen plaintext attack against SSL CBC initialization vectors

Matthias Andree reports:

Fetchmail version 6.3.9 enabled “all SSL workarounds” (SSL_OP_ALL)
which contains a switch to disable a countermeasure against certain
attacks against block ciphers that permit guessing the
initialization vectors, providing that an attacker can make the
application (fetchmail) encrypt some data for him – which is not
easily the case.
Stream ciphers (such as RC4) are unaffected.
Credits to Apple Product Security for reporting this.