---
title: "CVE-2026-84383: libheif - Heap Out-of-Bounds Write"
description: "libheif 1.22.0 to < 1.23.2 contains a heap out-of-bounds write caused by improper handling of nested iden and auxl references in Alpha planes during image decoding, letting remote attackers cause memory corruption via crafted files, exploit requires processing a crafted HEIF, HEIC, or AVIF file."
url: https://panop.io/threat-heartbeat/CVE-2026-84383/
---

# CVE-2026-84383 libheif - Heap Out-of-Bounds Write

libheif 1.22.0 to < 1.23.2 contains a heap out-of-bounds write caused by improper handling of nested iden and auxl references in Alpha planes during image decoding, letting remote attackers cause memory corruption via crafted files, exploit requires processing a crafted HEIF, HEIC, or AVIF file.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

Proof of concept available

Authentication

Not required

EPSS

0.61% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-84383)

## Details

Type

Heap Out-of-Bounds Write

Impact

Remote Code Execution

CVSS vector

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

Published

18 September 2026

Updated

15 October 2026

Weakness

[CWE-787](https://cwe.mitre.org/data/definitions/787.html)

## Vendor fix

Update to version 1.23.2 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-84383](https://nvd.nist.gov/vuln/detail/CVE-2026-84383)
- [https://github.com/strukturag/libheif/commit/f4fb8bde4704ebb46e46ff9fb94407c9774153b2](https://github.com/strukturag/libheif/commit/f4fb8bde4704ebb46e46ff9fb94407c9774153b2)
- [https://github.com/strukturag/libheif/releases/tag/v1.23.2](https://github.com/strukturag/libheif/releases/tag/v1.23.2)
- [https://github.com/strukturag/libheif/security/advisories/GHSA-g89c-p67h-r497](https://github.com/strukturag/libheif/security/advisories/GHSA-g89c-p67h-r497)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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