An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way keyboard prompt requests are parsed. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
https://www.libssh2.org/CVE-2019-3856.html
https://www.debian.org/security/2019/dsa-4431
https://security.netapp.com/advisory/ntap-20190327-0005/
https://seclists.org/bugtraq/2019/Apr/25
https://lists.debian.org/debian-lts-announce/2019/03/msg00032.html
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3856
https://access.redhat.com/errata/RHSA-2019:2399
https://access.redhat.com/errata/RHSA-2019:1943
https://access.redhat.com/errata/RHSA-2019:1791
https://access.redhat.com/errata/RHSA-2019:1652
https://access.redhat.com/errata/RHSA-2019:1175
https://access.redhat.com/errata/RHSA-2019:0679
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00003.html
http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00040.html