In OpenSSH 7.9, due to accepting and displaying arbitrary stderr output from the server, a malicious server (or Man-in-The-Middle attacker) can manipulate the client output, for example to use ANSI control codes to hide additional files being transferred.
Exploitability
AV:NAC:HPR:NUI:RScope
S:UImpact
C:HI:HA:N6.8/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N