作为我日常工作的一部分，我通过 SSH 连接到其中一台公司服务器。但是这次我收到了以下消息

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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
XX:XX..............
Please contact your system administrator.
Add correct host key in /Users/<user>/.ssh/known_hosts to get rid of this message.
Offending key in /Users/<user>/.ssh/known_hosts:43
RSA host key for <SERVER> has changed and you have requested strict checking.
Host key verification failed.

请解释在这种情况下可能会发生中间人攻击。