The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). NOTE: some reports state that 8.5 and 8.6 are also affected.
https://github.com/openssh/openssh-portable/compare/V_8_3_P1...V_8_4_P1
https://security.netapp.com/advisory/ntap-20200709-0004/
http://www.openwall.com/lists/oss-security/2020/12/02/1
https://anongit.mindrot.org/openssh.git/commit/?id=b3855ff053f5078ec3d3c653cdaedefaa5fc362d
https://github.com/ssh-mitm/ssh-mitm/blob/master/ssh_proxy_server/plugins/session/cve202014145.py
Source: MITRE
Published: 2020-06-29
Updated: 2022-04-28
Type: CWE-203
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 5.9
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 2.2
Severity: MEDIUM