CVE-2026-43908: OpenImageIO: Signed integer overflow in ConvertCbYCrYToRGB leads to heap out-of-bounds write in DPX 4:2:2 decoder

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.18.0 and 3.1.13.0, a signed 32-bit integer overflow in the pixel-loop index expression i * 3 inside ConvertCbYCrYToRGB() causes the function to compute a large negative pointer offset into the output buffer, producing an out-of-bounds write that crashes the process. This vulnerability is fixed in 3.0.18.0 and 3.1.13.0.