The QSslSocketBackendPrivate::transmit function in src_network_ssl_qsslsocket_openssl.cpp in Qt 4.6.3 and earlier allows remote attackers to cause a denial of service (infinite loop) via a malformed request.
https://hermes.opensuse.org/messages/12056605
http://www.vupen.com/english/advisories/2010/1657
http://secunia.com/advisories/46410
http://secunia.com/advisories/40389
http://qt.gitorious.org/qt/qt/commit/c25c7c9bdfade6b906f37ac8bad44f6f0de57597