CVE-2026-66040
FFmpeg Heap Out-of-Bounds Write via PNG/APNG eXIf Encoder
Description
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.
INFO
Published Date :
July 24, 2026, 8:18 p.m.
Last Modified :
Aug. 7, 2026, 12:35 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update FFmpeg to the patched version.
- Apply commit b506faf to FFmpeg.
- Avoid processing crafted PNG files.
- Validate PNG chunk sizes carefully.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-66040.
| URL | Resource |
|---|---|
| https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/b506fafec9a19fcbc2be5271875fd4a63d6615bc | Patch |
| https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23786 | Issue Tracking Patch |
| https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-via-png-apng-exif-encoder | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-66040 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-66040
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-66040 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-66040 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 07, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:* versions up to (including) 8.1.2 Added Reference Type VulnCheck: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/b506fafec9a19fcbc2be5271875fd4a63d6615bc Types: Patch Added Reference Type VulnCheck: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23786 Types: Issue Tracking, Patch Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-via-png-apng-exif-encoder Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 29, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-66040', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-27T14:33:26.371366Z'} {'id': 'CVE-2026-66040', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-28T00:00:00+00:00'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 27, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-66040', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-27T14:33:26.371366Z'} -
New CVE Received by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://code.ffmpeg.org/FFmpeg/FFmpeg', 'vendor': 'FFmpeg', 'product': 'FFmpeg', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '8.1.2'}, {'status': 'unaffected', 'version': 'b506fafec9a19fcbc2be5271875fd4a63d6615bc', 'versionType': 'git'}], 'defaultStatus': 'affected'}] Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-122 Added Reference https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/b506fafec9a19fcbc2be5271875fd4a63d6615bc Added Reference https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23786 Added Reference https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-via-png-apng-exif-encoder