The QSslSocket::sslErrors function in Qt before 4.6.5, 4.7.x before 4.7.6, 4.8.x before 4.8.5, when using certain versions of openSSL, uses an "incompatible structure layout" that can read memory from the wrong location, which causes Qt to report an incorrect error when certificate validation fails and might cause users to make unsafe security decisions to accept a certificate.