CVE-2026-62291
Publication date 20 August 2026
Last updated 27 August 2026
Ubuntu priority
Description
libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libheif | 26.04 LTS resolute |
Needs evaluation
|
| 24.04 LTS noble |
Fixed 1.17.6-1ubuntu4.8
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
Severity score breakdown
CVSS version: CVSS v3.0
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
References
Related Ubuntu Security Notices (USN)
- USN-8683-1
- libheif vulnerabilities
- 26 August 2026