It's an example of how things break if you upgrade to new versions of software. If you avoid going to new versions of software, and instead just backport the essential security fixes, there will be much fewer surprises like this.

Imagine you had a daily backup script that uses git to commit and push to a remote server perhaps managed by someone else. You then upgrade to the latest and greatest version of git to try to patch this vulnerability, and surprise, your backup script fails! Hope you weren't planning on spending the rest of the day getting the guys running the git server to implement a workaround, who might have already left for the weekend, leaving you with no backups or having to manually try to fix your git to work with that server again.