CVE-2025-62821Public exploit

Application crash via undersized HEIF source buffer

Published Jun 19, 2026 · Updated Jun 19, 2026

Out-of-bounds read in Microsoft HEIF Image Extensions 1.2.22.0 allows context-dependent attackers to crash WIC consumers via crafted HEIF files. CHEIFItemInfoEntry_GetDataSize can report success with a zero length, leading CHEIFStreamReader_ReadItemData to allocate one byte before CopyPixels passes an unchecked stride-by-height size to memmove. Opening or previewing the file with an installed extension is required, and the demonstrated consequence is an access-violation crash rather than code execution.

CVSS severity9.1
Critical
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Microsoft HEIF Image Extensions 1.2.22.0 allows context-dependent attackers to crash WIC consumers via crafted HEIF files. CHEIFItemInfoEntry_GetDataSize can report success with a zero length, leading CHEIFStreamReader_ReadItemData to allocate one byte before CopyPixels passes an unchecked stride-by-height size to memmove. Opening or previewing the file with an installed extension is required, and the demonstrated consequence is an access-violation crash rather than code execution.

The record

CVE
CVE-2025-62821
Published
Jun 19, 2026
Updated
Jun 19, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 19, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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.

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No observations available

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

Weakness, pattern, technique

CWE-125Out-of-bounds Read

Public exploit references

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

Technologies

Your stack

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Your stack

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