A flaw was found with the libssh API function sshscpnew() in versions before 0.9.3 and before 0.8.8. When the libssh SCP client connects to a server, the scp command, which includes a user-provided path, is executed on the server-side. In case the library is used in a way where users can influence the third parameter of the function, it would become possible for an attacker to inject arbitrary commands, leading to a compromise of the remote target.

A flaw was found in libssh builds using the OpenSSL backend for AES-GCM. In the decrypt path in src/libcrypto.c, the return value from EVPDecryptFinal() was checked incorrectly, so authentication tag verification failures were not handled as integrity failures. This could effectively remove integrity protection for affected AES-GCM sessions and allow an in-path attacker to modify plaintext on the wire without detection.

A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.