---
id: CVE-2026-84450
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, a crafted image item containing a clap property and an ispe width or
  height greater than INT32_MAX + 1 can reach crop calculations through
  heif_image_h…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'
cwe:
  - CWE-617
vendor: strukturag
product: libheif
affected:
  - 'libheif >= 1.19.0, < 1.23.3'
published: '2026-09-18'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T21:17:13.800'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84450'
references:
  - url: >-
      https://github.com/strukturag/libheif/commit/1c2df9c0e814f89716f3a4d85a444b2dbc63ad69
    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-gh5q-69gg-c964
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-18T19:30:30.489038Z'
epss: 0.004
epssPercentile: 0.31486
ingestedAt: '2026-09-18T16:45:41.395Z'
---

## Overview

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.3, a crafted image item containing a clap property and an ispe width or height greater than INT32_MAX + 1 can reach crop calculations through heif_image_handle_get_image_tiling(). Box_clap::left_rounded() or Box_clap::top_rounded() passes the image dimension minus one to Fraction::Fraction(), whose uint32_t constructor uses an assertion as input validation, causing assert-enabled builds to abort. Release builds can instead compute invalid crop geometry, and the tiling API returns dimensions that the normal decode security limits reject. This issue is fixed in version 1.23.3.

## Remediation

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