CVE-2026-128239

MEDIUM 5.5

GPAC through 26.07.0 NULL Pointer Dereference via MPEG-4 Form Handlers

CVSS Score

5.5

EPSS Score

0.0%

EPSS Percentile

0th

GPAC through 26.07.0 contains a NULL pointer dereference vulnerability in the MPEG-4 Form spatial-constraint handlers in src/compositor/mpeg4_form.c that lets attackers crash the process via unchecked group lookups. Attackers can supply a crafted XMT scene whose Form constraints reference a non-existent group, crashing tools like MP4Box during chapter import for denial of service.

CWE	CWE-476
Vendor	gpac
Product	gpac
Published	Nov 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

gpac / gpac

0 ≤ 26.07.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/gpac/gpac/issues/4029 github.com: https://github.com/gpac/gpac/commit/bc416b997622e43de65afab3bae9b7d05d72f2b0 github.com: https://github.com/gpac/gpac/blob/v26.07.0/src/compositor/mpeg4_form.c#L620-L621 github.com: https://github.com/sigdevel/pocs/blob/main/res/gpac/MP4Box/221/221_ab_apply_compositor_mpeg4_form_c_627.xmt github.com: https://github.com/gpac/gpac vulncheck.com: https://www.vulncheck.com/advisories/gpac-through-26.07.0-null-pointer-dereference-via-mpeg-4-form-handlers

Credits

Alexander A. Shvedov (sigdevel) Jean Le Feuvre