TL;DR: If your SSH key is of the ECDSA type with a key length of 521 bits, make a new one and take care to remove the public key belonging to the burned one from all authorized_keys files. Luckily, ecdsa-sha2-nistp521 is (AFAIK) not the default if you used ssh-keygen or PuttyGen with the default settings. https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-p521-bias.html
"The good news: the only affected key type is 521-bit ECDSA. That is, a key that appears in Windows PuTTYgen with ecdsa-sha2-nistp521 at the start of the 'Key fingerprint' box, or is described as 'NIST p521' when loaded into Windows Pageant, or has an id starting ecdsa-sha2-nistp521 in the SSH protocol or the key file. Other sizes of ECDSA, and other key algorithms, are unaffected. In particular, Ed25519 is not affected. "
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