Vuln ID: CVE-2026-62291

Published:  2026-08-18  22:17:02.877

Description: libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2×2 primary plane and a 256×256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. Track_Visual::decode_next_image_sample() calls transfer_channel_from_image_as() without checking that the auxiliary alpha dimensions match the main frame. The resulting inconsistent image reaches heif_track_decode_next_image() and then heif_context_encode_image(). In unc_encoder::encode(), unc_encoder_component_interleave::encode_tile() sizes its buffer with compute_tile_data_size_bytes() using the primary dimensions but copies each component using its actual plane dimensions. The oversized alpha plane is therefore copied beyond the allocation, causing an out-of-bounds write; the inverse size mismatch can also produce an out-of-bounds read. This issue is fixed in version 1.23.1.

Base Score: 5.3 – MEDIUM

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

Source: NVD.NIST.GOV