"Notes about this update: Security fix for CVE-2016-2315, CVE-2016-2324 (by updating to 2.5.5)."
So looks like they have backported the security fixes
EDIT: OK. So the fixes were backported
https://packages.debian.org/jessie/git
~ git --version git version 2.1.4
http://metadata.ftp-master.debian.org/changelogs/main/g/git/...
https://security-tracker.debian.org/tracker/source-package/g...