OSV-2025-600 Heap-buffer-overflow in generic_unpack

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=436037111 Crash type: Heap-buffer-overflow READ 2 Crash state: genericunpack Imf34::ScanLineInputFile::Data::readPixels Imf34::InputFile::readPixels...