OpenImageIO: Stack buffer overflow in OpenImageIO Cineon reader via unchecked numberOfElements

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1, A crafted cineon file can supply a numberofelements value greater than the format maximum of eight. cineoninput::open() uses that unchecked value as the loop bound while filling the fixed strings[8] array, writing pointers beyond the stack buffer and into adjacent state, resulting in memory corruption and denial of service. The affected implementation is identified by src/cineon.imageio/cineoninput.cpp, CineonInput::open(), numberOfElements, and strings[8], which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.20.0, 3.1.15.0, and 3.2.0.3-beta1.