Resolving SSH Permission Denied Errors Due to OpenSSH Version Vulnerabilities

If you have encountered errors while using SSH, such as the ones below:

Example 1:

foo@12.34.56.789: Permission denied (publickey).

Example 2:

sign_and_send_pubkey: no mutual signature supported
foo@12.34.56.789: Permission denied (publickey).

It's possible that you may be using an older version of OpenSSH on your server that is vulnerable to the SHA-1 algorithm, which was disabled in OpenSSH version 8.8 (2021-09-26). If you're certain that you've correctly added the public key to your server, this could be the cause of the …

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