In opencv/modules/imgcodecs/src/utils.cpp, functions FillUniColor and FillUniGray do not check the input length, which can lead to integer overflow. If the image is from remote, may lead to remote code execution or denial of service. This affects Opencv 3.3 (corresponding with OpenCV-Python 3.3.0.9) and earlier.
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