server and client side remote code execution through a buffer overflow in all git versions before 2.7.1 (unpublished ᴄᴠᴇ-2016-2324 and ᴄᴠᴇ‑2016‑2315)
Ubuntu 14.04 的 git 還在 1.x,只好靠 PPA 抓新版本:
sudo add-apt-repository ppa:git-core/ppa
sudo aptitude update && sudo aptitude upgrade