The SSH transport protocol with certain OpenSSH extensions, found in
OpenSSH before 9.6 and other products, allows remote attackers to bypass
integrity checks such that some packets are omitted (from the extension
negotiation message), and a client and server may consequently end up
with a connection for which some security features have been downgraded
or disabled, aka a Terrapin attack. This occurs because the SSH Binary
Packet Protocol (BPP), implemented by these extensions, mishandles the
handshake phase and mishandles use of sequence numbers.
Our libssh2 packages were also affected, this update fixes the issue.