Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

libheif is a HEIF and AVIF file format decoder and encoder. Prior to 1.23.2, the public heif_region_item_add_region_inline_mask_data() function in libheif/api/libheif/heif_regions.cc accepts mask_data_len without verifying that it equals the byte count required by width and height. A later heif_region_get_mask_image() call derives the read length from the region geometry, so an undersized stored buffer causes heif_region_get_inline_mask_image() to read beyond the heap allocation and copy adjacent bytes into the returned monochrome mask image. This can disclose heap data or crash an application that constructs region metadata through the writer API, while the file-parsing path is not affected because it validates the canonical mask size. This issue is fixed in version 1.23.2.