CVE-2021-44921Public exploit

Application crash via zero-size nested media box

Published Dec 21, 2021 · Updated Aug 4, 2024

Null pointer dereference in GPAC 1.1.0 allows local users to crash MP4Box by opening a crafted ISO media file with user interaction. A zero-size nested box makes gf_isom_box_parse_ex return end-of-stream instead of rejecting the invalid file, leaving a null box pointer for gf_isom_parse_movie_boxes_internal to dereference. Triggering the fault requires MP4Box to process the crafted file, and the demonstrated consequence is a segmentation fault that terminates the application.

CVSS severity5.5
Medium
EPSS probability0.61%
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 1.1.0 allows local users to crash MP4Box by opening a crafted ISO media file with user interaction. A zero-size nested box makes gf_isom_box_parse_ex return end-of-stream instead of rejecting the invalid file, leaving a null box pointer for gf_isom_parse_movie_boxes_internal to dereference. Triggering the fault requires MP4Box to process the crafted file, and the demonstrated consequence is a segmentation fault that terminates the application.

The record

CVE
CVE-2021-44921
Published
Dec 21, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 21, 2021CVE 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

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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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