CVE-2021-40576Public exploit

Process crash via unchecked hint media header

Published Jan 13, 2022 · Updated Aug 4, 2024

Null pointer dereference in GPAC MP4Box 1.0.1 allows local users to crash the process by inspecting a crafted MP4 file. During track inspection, gf_isom_get_payt_count reaches GetHintFormat, which dereferences a missing hmhd media-header pointer before checking it for null. The file must be supplied to MP4Box and processed with -info; the demonstrated consequence is a segmentation fault that terminates that MP4Box process.

CVSS severity5.5
Medium
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in GPAC MP4Box 1.0.1 allows local users to crash the process by inspecting a crafted MP4 file. During track inspection, gf_isom_get_payt_count reaches GetHintFormat, which dereferences a missing hmhd media-header pointer before checking it for null. The file must be supplied to MP4Box and processed with -info; the demonstrated consequence is a segmentation fault that terminates that MP4Box process.

The record

CVE
CVE-2021-40576
Published
Jan 13, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference

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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