CVE-2026-66040Network attack vector

Heap corruption via eXIf size underallocation

Published Jul 24, 2026 · Updated Jul 24, 2026

Heap out-of-bounds write in FFmpeg 8.1.2 and earlier allows remote attackers to corrupt memory through a crafted PNG eXIf chunk. Repeated IFD entries can reference one large value, causing add_exif_profile_size() to underallocate before png_write_chunk() serializes expanded data past the heap buffer. A PNG or APNG encoding workflow must process the file; exploitation deterministically crashes the process and can execute arbitrary code.

CVSS severity8.7
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap out-of-bounds write in FFmpeg 8.1.2 and earlier allows remote attackers to corrupt memory through a crafted PNG eXIf chunk. Repeated IFD entries can reference one large value, causing add_exif_profile_size() to underallocate before png_write_chunk() serializes expanded data past the heap buffer. A PNG or APNG encoding workflow must process the file; exploitation deterministically crashes the process and can execute arbitrary code.

The record

CVE
CVE-2026-66040
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
FFmpeg
Product
FFmpeg
Classifications
CWE-122, CAPEC-92, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 24, 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=0 <=8.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FFmpeg · FFmpegversion=0 <=8.1.2

Published CVSS scores

8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CAPEC-92Forced Integer Overflow
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

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Your stack

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