CVE-2026-84383Public exploitNetwork attack vectorHinoki check available

Remote code execution via duplicate Alpha planes

Published Sep 18, 2026 · Updated Sep 18, 2026

Heap out-of-bounds write in libheif 1.22.0 through 1.23.1 allows remote attackers to execute code through a crafted HEIF, HEIC, or AVIF file. Nested iden and auxl references create duplicate Alpha planes, and scale_nearest_neighbor() allocates from the first plane's 8-bit depth before writing later 16-bit samples into that buffer. Any application that passes an untrusted file to heif_decode_image() is exposed without nondefault options; the write extent and values are attacker-controlled.

CVSS severity9.8
Critical
EPSS probability0.61%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Heap out-of-bounds write in libheif 1.22.0 through 1.23.1 allows remote attackers to execute code through a crafted HEIF, HEIC, or AVIF file. Nested iden and auxl references create duplicate Alpha planes, and scale_nearest_neighbor() allocates from the first plane's 8-bit depth before writing later 16-bit samples into that buffer. Any application that passes an untrusted file to heif_decode_image() is exposed without nondefault options; the write extent and values are attacker-controlled.

The record

CVE
CVE-2026-84383
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
Struktur AG
Product
libheif
Classifications
T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.22.0, < 1.23.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Struktur AG · libheifversion=>= 1.22.0, < 1.23.2

Published CVSS scores

9.8GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started