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CVE Record

CVE-2026-9567: GPAC MP4Box isom_intern.c MergeFragment null pointer dereference

A security flaw has been discovered in GPAC up to 2.4.0. Affected is the function MergeFragment of the file src/isomedia/isom_intern.c of the component MP4Box. The manipulation results in null pointer dereference. The attack needs to be approached locally. The exploit has been released to the public and may be used for attacks. The patch is identified as 525bf1af642c30af04e4df5345e6d798c0a4d8a1. It is advisable to implement a patch to correct this issue.

MediumCVSS 4.8Not KEV-listed Updated
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Glexia's Take moderate

Analyst readout for executives and security teams

Plain-English summary

This flaw can make GPAC MP4Box crash when handling a crafted fragmented MP4 operation. It is not described as remote code execution or data theft. Business impact is mainly denial of service in local or automated media-processing workflows that run affected GPAC versions on untrusted files.

Executive priority

Treat this as a moderate operational-risk issue. It is unlikely to be enterprise-critical by itself, but it deserves prompt remediation where GPAC handles external media because public exploit material is reported and crashes can disrupt automated processing.

Technical view

CVE-2026-9567 affects GPAC MP4Box through a null pointer dereference in MergeFragment in src/isomedia/isom_intern.c. Sources list GPAC 2.0 through 2.4.0 as affected. CVSS 4.0 is 4.8 with local attack vector, low complexity, low privileges, no user interaction, and low availability impact.

Likely exposure

Exposure is most likely where GPAC MP4Box is installed on workstations, build systems, or media pipelines and processes files from users, partners, crawlers, or uploads. Public-facing exposure is not directly indicated because the source describes a local attack path.

Exploitation context

The source bundle states a public exploit exists, but CISA KEV status is false and no cited source confirms active exploitation. The practical concern is crash-driven denial of service after a local or pipeline context processes malicious media input.

Researcher notes

Evidence supports null pointer dereference and availability impact only. Do not infer code execution, remote reachability, or broad product impact beyond GPAC versions listed. The public PoC reference increases reproducibility risk, but KEV is false and active exploitation is not established.

Mitigation direction

  • Apply patch commit 525bf1af642c30af04e4df5345e6d798c0a4d8a1 where applicable.
  • Track GPAC advisories for a release containing the fix.
  • Avoid processing untrusted MP4 inputs with affected MP4Box versions.
  • Run media-processing jobs with isolation, least privilege, and restart controls.
  • Prioritize patching automated workflows that consume external media.

Validation and detection

  • Inventory GPAC and MP4Box versions across workstations and media-processing systems.
  • Identify workflows processing MP4 files from external or untrusted sources.
  • Confirm whether the patch commit is present in deployed builds.
  • Review job logs for unexpected MP4Box crashes or denial-of-service symptoms.
  • Check GPAC issue 3549 and vendor guidance for fix status.
Prepared
Confidence
medium
Sources
7

Public sources used

Based on public source material and reviewed before publication.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-404: Exact CWE lookup

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cwe · low confidence lookup

CWE-476: Exact CWE lookup

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cve · low confidence lookup

CVE-2026-9567 mapping review

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Vulnerability profile CVE Program record
Severity
Medium
CVSS
4.8 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

4 CVSS vectors
6 Timeline events
1 ADP providers
8 Source links

SSVC decision data

CISA-ADP CISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: partial

CVSS vector scores

4 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

Score Version Severity Vector Exploit Impact Source
4.8 CVSS 4.0 Medium CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P — — VulDB
3.3 CVSS 3.1 Low CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C 1.8 1.4 VulDB
3.3 CVSS 3.0 Low CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C 1.8 1.4 VulDB
1.7 CVSS 2.0 Low AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:OF/RC:C 3.1 2.9 VulDB

Vulnerability scoring details

Base CVSS 4.0 score

4.8 Medium
CVSS 4.0 vector shape for CVE-2026-9567 Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timeline VulDB

    Advisory disclosed

  2. Source timeline VulDB

    VulDB entry created

  3. CVE reserved CVE Program

    The CVE ID was reserved by the assigning CNA.

  4. Source timeline VulDB

    VulDB entry last update

  5. CVE published CVE Program

    The CVE record was published.

  6. CVE updated CVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADP CISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

Vendor Product Version / package Status
n/a GPAC 2.0, 2.1, 2.2, 2.3, 2.4.0 Listed
Weakness

CWE details

CWE-404CWE-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-404 · source CWE mapping

Improper Resource Shutdown or Release

Improper Resource Shutdown or Release represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligence Same-CWE CVEs
CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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