FFmpeg up to 8.1.2 PNG/APNG encoders png_write_chunk out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k4.70

Summaryinfo

A vulnerability was found in FFmpeg up to 8.1.2. It has been classified as critical. This affects the function png_write_chunk of the component PNG/APNG encoders. This manipulation causes out-of-bounds write. This vulnerability is tracked as CVE-2026-66040. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in FFmpeg up to 8.1.2 and classified as critical. Affected by this vulnerability is the function png_write_chunk of the component PNG/APNG encoders. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

FFmpeg through 8.1.2, fixed in commit b506faf, contains a heap out-of-bounds write vulnerability in the native PNG and APNG encoders that allows remote attackers to corrupt heap memory by supplying a crafted PNG image with a malicious eXIf chunk. Attackers can craft an eXIf chunk where multiple IFD entries reference the same large value payload, causing canonical serialization to expand the output far beyond the undersized allocation estimated by add_exif_profile_size(), resulting in png_write_chunk() writing tens of thousands of bytes past the buffer boundary, leading to deterministic heap corruption, process crash, and potentially arbitrary code execution.

The advisory is shared at code.ffmpeg.org. This vulnerability is known as CVE-2026-66040 since 07/23/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Applying the patch b506faf is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: b506faf

Timelineinfo

07/23/2026 CVE reserved
07/24/2026 +1 days Advisory disclosed
07/24/2026 +0 days VulDB entry created
07/24/2026 +0 days VulDB entry last update

Sourcesinfo

Product: ffmpeg.org

Advisory: code.ffmpeg.org
Status: Confirmed

CVE: CVE-2026-66040 (🔒)
GCVE (CVE): GCVE-0-2026-66040
GCVE (VulDB): GCVE-100-383017

Entryinfo

Created: 07/24/2026 22:22
Changes: 07/24/2026 22:22 (55)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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