---
id: CVE-2026-84451
title: libheif is a HEIF and AVIF file format decoder and encoder
summary: >-
  libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until
  1.23.3, the no-icef full-item branch of
  unc_decoder::get_compressed_image_data_uncompressed() in
  libheif/codecs/uncompressed/unc_decoder.cc retains an addition…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cwe:
  - CWE-125
vendor: strukturag
product: libheif
affected:
  - 'libheif >= 1.19.0, < 1.23.3'
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T16:17:13.640'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84451'
references:
  - url: >-
      https://github.com/strukturag/libheif/commit/8bfed9a9ed008e4ef28abc736284a90d3cba754f
    label: security-advisories@github.com
  - url: 'https://github.com/strukturag/libheif/releases/tag/v1.23.3'
    label: security-advisories@github.com
  - url: >-
      https://github.com/strukturag/libheif/security/advisories/GHSA-hh47-fhqr-cj2r
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-18T16:45:41.396Z'
epss: 0.00446
epssPercentile: 0.38171
---

## Overview

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.3, the no-icef full-item branch of unc_decoder::get_compressed_image_data_uncompressed() in libheif/codecs/uncompressed/unc_decoder.cc retains an addition-based range check that can wrap when a crafted uncompressed tile grid produces a large range_start_offset and range_size. The overflow makes the bounds comparison pass and allows heif_image_handle_decode_image_tile() to call memcpy() with an invalid source pointer and a very large length when decoding a valid high-index advertised tile. This incomplete remediation of CVE-2026-62292 can reliably crash tile-processing applications, while whole-image decoding is not claimed to reach the demonstrated path. This issue is fixed in version 1.23.3.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.