CVE-2025-29769 — Heap-based Buffer Overflow in Libvips

libvips is a demand-driven, horizontally threaded image processing library. The heifsave operation could incorrectly determine the presence of an alpha channel in an input when it was not possible to determine the colour interpretation, known internally within libvips as "multiband". There aren't many ways to create a "multiband" input, but it is possible with a well-crafted TIFF image. If a "multiband" TIFF input image had 4 channels and HEIF-based output was requested, this led to libvips crea…