vips_foreign_load_gif_scan_image in foreign/gifload.c in libvips before 8.8.2 tries to access a color map before a DGifGetImageDesc call, leading to a use-after-free.
https://github.com/libvips/libvips/compare/v8.8.1...v8.8.2
https://github.com/libvips/libvips/commit/ce684dd008532ea0bf9d4a1d89bacb35f4a83f4d