CVE-2021-4043Known exploitationPublic exploit

Process crash via null entries iteration

Published Feb 4, 2022 · Updated Nov 8, 2024

NULL pointer dereference in GPAC before 1.1.0 allows local users to crash MP4Box by processing a crafted media file. During ISO media cleanup, gitn_box_del iterates ptr->entries according to nb_entries even when the entries pointer is null, causing a read near address zero. A local user must cause MP4Box to parse the crafted file; the demonstrated consequence is a process crash, with no reported data disclosure or modification.

CVSS severity5.8
Medium
EPSS probability4.61%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in GPAC before 1.1.0 allows local users to crash MP4Box by processing a crafted media file. During ISO media cleanup, gitn_box_del iterates ptr->entries according to nb_entries even when the entries pointer is null, causing a read near address zero. A local user must cause MP4Box to parse the crafted file; the demonstrated consequence is a process crash, with no reported data disclosure or modification.

The record

CVE
CVE-2021-4043
Published
Feb 4, 2022
Updated
Nov 8, 2024
Vendor
Debian
Product
Debian GNU/Linux
Classifications
CWE-476, T1204.002, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 30, 2024Exploitation reportedHistorical CISA KEV catalog entry, subsequently removed
  3. Nov 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=11.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Debian · Debian GNU/Linuxversion=11.0
GPAC Project · GPACversion=0 <1.1.0; version=unspecified <1.1.0

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.8huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1204.002Malicious File
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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