Double free vulnerability in the ssh_packet_kexinit function in kex.c in libssh 0.5.x and 0.6.x before 0.6.4 allows remote attackers to cause a denial of service via a crafted kexinit packet.

The RAND_bytes function in libssh before 0.6.3, when forking is enabled, does not properly reset the state of the OpenSSL pseudo-random number generator (PRNG), which causes the state to be shared between children processes and allows local users to obtain sensitive information by leveraging a pid collision.

The publickey_from_privatekey function in libssh before 0.5.4, when no algorithm is matched during negotiations, allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a "Client: Diffie-Hellman Key Exchange Init" packet.