OpenCV 3.0.0 has a double free issue that allows attackers to execute arbitrary code. This issue was fixed in OpenCV version 3.3.1 (corresponding to OpenCV-Python and and OpenCV-Contrib-Python 3.3.1.11).
3.3.1.11Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:HCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H