CVE-2026-62289
libheif: Integer underflow in Fraction constructor via double clap transform application
libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF or AVIF file containing a clean aperture box can reduce an image dimension to zero and crash or corrupt tiling results when heif_image_handle_get_image_tiling(handle, 1, &tiling) is called. ImageItem::get_heif_image_tiling() returns already transformed dimensions, and process_image_transformations_on_tiling() applies the clean aperture transformation again. The second application passes zero to Box_clap::left_rounded(0), where image_width minus one underflows and constructs Fraction(0xFFFFFFFF, 2). Debug builds reach an assertion and abort, while release builds can return a corrupt crop and zero-width tiling result. The affected implementation spans libheif/image-items/image_item.cc, libheif/context.cc, and libheif/box.cc. This issue is fixed in version 1.23.1.
| CWE | CWE-191 CWE-617 |
| Vendor | strukturag |
| Product | libheif |
| Published | Aug 18, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L