I want to host the repository https://github.com/cmitiisertvm/cmitiisertvm.github.io on github pages and use the custom subdomain cmit.iisertvm.ac.in. I added a CNAME record for cmitiisertvm.github.io in my domain’s DNS settings, but when I tried to add a CNAME record for the subdomain in the respository, it shows: The CNAME cmit.iisertvm.ac.in is already taken. There are no other repositories using this CNAME currently, so I can’t figure out the problem. Please help.
Hey @thesagniksaha, it looks like this got resolved, is there any suggestions you can write up for folks with the same issue you had? Thanks!
The problem that happened here was a case of subdomain takeover, and is a serious issue. If you create a subdomain CNAME record in your domain’s DNS settings that points to a github username and don’t update the custom domain address in your repository’s Settings > GitHub Pages within a stipulated amount of time, your subdomain could be taken over by someone else, and if you try to add that subdomain to a repository later, it will show that “The CNAME subdomain.domain.com is already taken”.
Patrik has written a lot about subdomain takeovers in his blog here: https://0xpatrik.com/
Hope this was useful.
Were you able to resolve the takeover? How did you determine that it had been taken over in the first place?
I have the same issue yet to be resolved.
Got the same error as well when I tried to use my custom domain “lo.fish”. Maybe a cache problem?
Looked up on Stack Overflow and tried everything but to no avail.
here is the repo: https://github.com/CAST3LLA/lo.fish/