CVE-2026-63422: Heap-based Buffer Overflow

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1, A valid tiled openexr image whose width is not a multiple of its tile width can trigger an overflow when a caller reads a partial edge-tile rectangle. openexrinput::read_native_tiles() copies each row into the caller buffer using the padded whole-tile scanline_stride rather than user_scanline_bytes for the requested rectangle, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/openexr.imageio/exrinput.cpp, OpenEXRInput::read_native_tiles(), partial edge tile, user_scanline_bytes, and scanline_stride, which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1.