Use-After-Free Vulnerability in GPAC Product by GPAC
CVE-2026-128240

6.8MEDIUM

Key Information:

Vendor

Gpac

Status
Gpac
Vendor
CVE Published:
13 November 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-128240?

GPAC versions up to 26.07.0 exhibit a use-after-free vulnerability due to improper handling of scene prototypes. Specifically, the function gf_sg_proto_del() in src/scenegraph/vrml_proto.c fails to manage the memory correctly when gf_sg_reset() frees prototypes that are still in use by various scene commands. By crafting specific XMT/BT scenes that declare these prototypes, an attacker can manipulate freed memory access, leading to a potential crash of the application when processed by MP4Box. This flaw raises serious concerns about the stability and reliability of GPAC in handling scene data.

Affected Version(s)

gpac 0 <= 26.07.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-128240 - Proof of Concept

References

https://github.com/gpac/gpac/issues/4031
issue-tracking
https://github.com/gpac/gpac/commit/a2e5c62c213b5329a4572...
patch
https://github.com/gpac/gpac/blob/v26.07.0/src/scenegraph...
technical-description

CVSS V4

Score:
6.8
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Alexander A. Shvedov (sigdevel)
Jean Le Feuvre
.