CVE-2026-62291

Heap corruption via mismatched alpha-plane copy

Published Aug 18, 2026 · Updated Aug 18, 2026

Heap corruption in libheif before 1.23.1 allows attackers to corrupt process memory via crafted HEIF sequences during decode and re-encode. Track_Visual::decode_next_image_sample() attaches an auxiliary alpha plane without verifying that its dimensions match the main frame, and unc_encoder_component_interleave::encode_tile() then allocates from the primary dimensions but copies each component using its actual plane size, leading to out-of-bounds writes and reads. Reachability requires an application path that decodes and then re-encodes attacker-supplied HEIF or AVIF sequence data; the immediate consequence is process corruption or crash, while code execution depends on a separate memory-corruption exploit chain.

CVSS severity5.3
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap corruption in libheif before 1.23.1 allows attackers to corrupt process memory via crafted HEIF sequences during decode and re-encode. Track_Visual::decode_next_image_sample() attaches an auxiliary alpha plane without verifying that its dimensions match the main frame, and unc_encoder_component_interleave::encode_tile() then allocates from the primary dimensions but copies each component using its actual plane size, leading to out-of-bounds writes and reads. Reachability requires an application path that decodes and then re-encodes attacker-supplied HEIF or AVIF sequence data; the immediate consequence is process corruption or crash, while code execution depends on a separate memory-corruption exploit chain.

The record

CVE
CVE-2026-62291
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Struktur AG
Product
libheif
Classifications
CWE-787, CWE-125, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 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=< 1.23.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Struktur AG · libheifversion=< 1.23.1

Published CVSS scores

5.3GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-125Out-of-bounds Read
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo