Gitlab Runner - Config SSH CBC Cipher

I’m trying to get gitlab runner to build over SSH, but my server only supports CBC ciphers. I saw somewhere that CBC was not enabled by default in the client configs, but that it could be enabled if need be. For the life of me, I can’t find out how/where. Does anybody know how to enable CBC cipers for SSH runners?

I have the same problem. Hopefully someone will reply with solution