In OpenCV 3.3.1 (corresponding with OpenCV-Python 3.3.1.11), a heap-based buffer over-read exists in the function cv::HdrDecoder::checkSignature in modules/imgcodecs/src/grfmt_hdr.cpp.
3.4.1.153.4.1.15Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:NI:NA:H7.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H