If you fixed a file on your local branch, it will be pushed to a single remote branch which is the branch upstream.
If you have many remote branches that needs this fix. You need to merge the commit to all those branches. First locally, and then push the changes.
It has to be done manually, or using some script.
git checkout some_local_branch
git cherry-pick <hash of the fix>
git checkout another_local_branch
git cherry-pick <hash of the fix>
....
git push
The last git push will either push all your branches together or just some branches. That depends on your settings.