CVE-2026-66041Public exploitNetwork attack vector

Heap corruption via stale vf_quirc buffer sizing

Published Jul 24, 2026 · Updated Jul 24, 2026

Heap out-of-bounds write in FFmpeg 7.0 through 8.1.2 allows attackers to corrupt memory via a crafted PGS/SUP subtitle file. The vf_quirc filter retains the first frame's libquirc grayscale buffer and passes a larger later frame to av_image_copy_plane() without resizing that buffer. Processing a subtitle whose later presentation has larger dimensions can crash the process and permits code execution through heap corruption.

CVSS severity7.7
High
EPSS probability0.54%
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 7.0 through 8.1.2 allows attackers to corrupt memory via a crafted PGS/SUP subtitle file. The vf_quirc filter retains the first frame's libquirc grayscale buffer and passes a larger later frame to av_image_copy_plane() without resizing that buffer. Processing a subtitle whose later presentation has larger dimensions can crash the process and permits code execution through heap corruption.

The record

CVE
CVE-2026-66041
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
FFmpeg
Product
FFmpeg
Classifications
CWE-787, 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=7.0 <=8.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FFmpeg · FFmpegversion=7.0 <=8.1.2

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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