CVE-2026-63420: OpenImageIO: PSD RawColor indexed image out-of-bounds read in `interleave_row`

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, An indexed psd with transparency metadata creates fewer stored channelbuffers than the spec.nchannels value advertised by the rawcolor path. when oiio:rawcolor or psd:rawdata is enabled, psdinput::readnativescanline() passes spec.nchannels to psdinput::interleaverow(), which indexes beyond channelbuffers, resulting in a heap out-of-bounds read and process crash. The affected implementation is identified by src/psd.imageio/psdinput.cpp, PSDInput::readnativescanline(), PSDInput::interleaverow(), oiio:RawColor, psd:RawData, channelbuffers, and spec.nchannels, 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.