CVE-2026-84444Public exploitNetwork attack vector

Heap corruption via unchecked tile plane dimensions

Published Sep 18, 2026 · Updated Sep 18, 2026

Out-of-bounds write in libheif before 1.23.2 allows attackers to corrupt heap memory through an uncompressed tiled-image API call. ImageItem_uncompressed::add_image_tile() skips component-size validation, so encode_tile() allocates from declared geometry but copies the larger actual planes. The path requires WITH_UNCOMPRESSED_CODEC and partially untrusted tile data; the published reproducer demonstrates a deterministic heap overwrite.

CVSS severity7.4
High
EPSS probability0.48%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in libheif before 1.23.2 allows attackers to corrupt heap memory through an uncompressed tiled-image API call. ImageItem_uncompressed::add_image_tile() skips component-size validation, so encode_tile() allocates from declared geometry but copies the larger actual planes. The path requires WITH_UNCOMPRESSED_CODEC and partially untrusted tile data; the published reproducer demonstrates a deterministic heap overwrite.

The record

CVE
CVE-2026-84444
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
Struktur AG
Product
libheif
Classifications
CWE-787
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

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Is a vulnerable build present?

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

  1. Affected versionversion=< 1.23.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Struktur AG · libheifversion=< 1.23.2

Published CVSS scores

7.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/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.

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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

CWE-787Out-of-bounds Write

Public exploit references

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Technologies

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