---
id: CVE-2026-84384
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
  1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause
  decompress_brotli() and do_inflate() to grow accumulated output without an
  effective s…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-409
vendor: strukturag
product: libheif
affected:
  - 'libheif >= 1.19.0, < 1.23.2'
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:16.907'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84384'
references:
  - url: >-
      https://github.com/strukturag/libheif/commit/21893e8f66c8b79363ca2809391b07d35e1a95ec
    label: security-advisories@github.com
  - url: 'https://github.com/strukturag/libheif/releases/tag/v1.23.2'
    label: security-advisories@github.com
  - url: >-
      https://github.com/strukturag/libheif/security/advisories/GHSA-24wx-9w62-c96w
    label: security-advisories@github.com
  - url: >-
      https://github.com/strukturag/libheif/security/advisories/GHSA-24wx-9w62-c96w
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T17:30:24.859004Z'
ingestedAt: '2026-09-18T16:45:41.393Z'
epss: 0.00524
epssPercentile: 0.43457
---

## Overview

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause decompress_brotli() and do_inflate() to grow accumulated output without an effective size limit or MemoryHandle accounting. The brotli path has no output bound, while the zlib path checks only a small temporary buffer in a branch that valid streams do not reach, and overlapping icef units can decompress the same payload repeatedly. HeifContext::interpret_heif_file_images() processes multiple compressed metadata items during file opening, allowing a small file to consume unbounded memory and terminate the process. This issue is fixed in version 1.23.2.

## Remediation

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