Here are the Updates which Tor Browser 4.0.4 is carrying,

Update Firefox to 31.5.0esr Update OpenSSL to 1.0.1l Update NoScript to 2.6.9.15 Update HTTPS-Everywhere to 4.0.3

Bugs and Flaws patched in latest Tor 4.0.4 Browser,

Bug 14203: Prevent meek from displaying an extra update notification Bug 14849: Remove new NoScript menu option to make permissions permanent Bug 14851: Set NoScript pref to disable permanent permissions

The Latest version, Tor Browser 4.0.4 can be downloaded from Tor Projects official website. Tor has said that it was not affected by the OpenSSL vulnerability but it has anyhow fixed the bug in this stable release.