# CVE-2026-124031: GPAC through 26.07.0 Type Confusion via drawable_get_aspect_2d_mpeg4

Status: published. Published: 2026-11-06. Updated: 2026-11-09.

GPAC through 26.07.0 contains a type confusion vulnerability in drawable_get_aspect_2d_mpeg4() and TraverseShape() that casts a Shape's appearance node to M_Appearance without checking its node tag. Attackers can supply a crafted XMT file placing another node type, such as Conditional, in the appearance field to trigger an invalid memory read and crash MP4Box.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/gpac/gpac/commit/43a8329a90ae2907716b593cc3746458516c7c39

## Affected products and versions

- gpac / gpac: ≥ 0; ≤ 26.07.0 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.12% as of 2026-11-09; percentile 1.94%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-843

## Exploit evidence

- exploit: https://github.com/sigdevel/pocs/blob/main/res/gpac/MP4Box/222/222_gf_node_get_tag_compositor_texturing_c_370.xmt (CNA: VulnCheck)

## References

- https://github.com/gpac/gpac/issues/4030 (CNA: VulnCheck; issue-tracking)

- https://github.com/gpac/gpac (CNA: VulnCheck; product)

- https://github.com/gpac/gpac/commit/43a8329a90ae2907716b593cc3746458516c7c39 (CNA: VulnCheck; patch)

- https://github.com/sigdevel/pocs/blob/main/res/gpac/MP4Box/222/222_gf_node_get_tag_compositor_texturing_c_370.xmt (CNA: VulnCheck; exploit)

- https://github.com/gpac/gpac/blob/v26.07.0/src/compositor/drawable.c#L564-L565 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/gpac-through-26.07.0-type-confusion-via-drawable-get-aspect-2d-mpeg4 (CNA: VulnCheck; third-party-advisory)

- https://github.com/gpac/gpac (disclosure@vulncheck.com)

- https://github.com/gpac/gpac/blob/v26.07.0/src/compositor/drawable.c#L564-L565 (disclosure@vulncheck.com)

- https://github.com/gpac/gpac/commit/43a8329a90ae2907716b593cc3746458516c7c39 (disclosure@vulncheck.com)

- https://github.com/gpac/gpac/issues/4030 (disclosure@vulncheck.com)

- https://github.com/sigdevel/pocs/blob/main/res/gpac/MP4Box/222/222_gf_node_get_tag_compositor_texturing_c_370.xmt (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/gpac-through-26.07.0-type-confusion-via-drawable-get-aspect-2d-mpeg4 (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124031; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124031; retrieved 2026-11-10; source updated 2026-11-09

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-124031; retrieved 2026-11-09; source updated Not reported

Revision: 53e9dd421dc8d6d1acffc50e708576e3cde4253a0daf527be82ccf6598817bf9

Canonical: https://y2.dev/cve/CVE-2026-124031

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