Integer Overflow and Out-of-Bounds Write in FFmpeg libavformat

Publication date: 2026-04-16

Last updated on: 2026-04-20

Assigner: MITRE

Description

FFmpeg before 8.1 has an integer overflow and resultant out-of-bounds write via CENC (Common Encryption) subsample data to libavformat/mov.c.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-04-16

Last Modified

2026-04-20

Generated

2026-07-06

AI Q&A

2026-04-16

EPSS Evaluated

2026-07-05

NVD

CVE-2026-40962

EUVD

EUVD-2026-23153

Affected Vendors & Products

Vendor	Product	Version / Range
ffmpeg	ffmpeg	to 8.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-190	The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

Executive Summary

This vulnerability exists in FFmpeg versions before 8.1 and involves an integer overflow that leads to an out-of-bounds write. It occurs specifically in the handling of CENC (Common Encryption) subsample data within the libavformat/mov.c component.

Impact Analysis

The integer overflow and out-of-bounds write can potentially lead to corruption of memory, which may cause the application to crash or behave unpredictably. This could be exploited to compromise the integrity, confidentiality, or availability of the system running the vulnerable FFmpeg version.

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