contrib/completion/git-prompt.sh in Git before 1.9.3 does not sanitize branch names in the PS1 variable, allowing a malicious repository to cause code execution.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H