# CVE-2025-71438: GPAC MP4Box out-of-bounds read in AC4 descriptor parsing

Source: https://junglewise.ai/threats/cve-2025-71438-an-out-of-bounds-read-in-gf-odf-ac4-cfg-dsi-v1-odf-descriptors-c  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2025-71438 · Severity: info · Published 2026-10-21

GPAC's MP4Box is a multimedia processing tool that handles video and audio file formats. An out-of-bounds memory read in its AC4 audio descriptor parser can crash the application when processing a maliciously crafted AC4 media file, causing a denial of service.

Technologies: [GPAC Project MP4Box](https://junglewise.ai/threats/technologies/gpac-project-mp4box). Vendors: [GPAC Project](https://junglewise.ai/threats/vendors/gpac-project).

## Quick answers

**Is CVE-2025-71438 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-71438 being exploited in the wild.

**How severe is CVE-2025-71438?** Informational severity, published 21 October 2026.

**Which products and versions are affected?** GPAC Project MP4Box before 26.07.0.

**Is there a fix for CVE-2025-71438?** Yes: fixed in v26.07.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-71438 attacked?** It is attacked with local access or over the network, in a software library.

**Am I affected by CVE-2025-71438?** Check whether you run GPAC Project MP4Box at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in v26.07.0

## Technical details

An out-of-bounds read vulnerability exists in the gf_odf_ac4_cfg_dsi_v1 function (odf/descriptors.c:2179) where the frame_rate_index is not validated before indexing into fixed-size lookup tables (AC4_SAMPLE_DELTA_TABLE_48 or AC4_MEDIA_TIMESCALE_48). An attacker can supply a crafted AC4 file with an invalid frame_rate_index to trigger a segmentation fault via a read to the zero page. This requires local or network-accessible file input to MP4Box.

## Affected products

- GPAC Project MP4Box before 26.07.0

## Timeline

- 2025-07-16: disclosed
- 2025-10-21: patched: Commit 13eb5b76560aaf7813b865a2ad433258478e2695 with AC4 and fuzzing fixes

## References

- [https://github.com/gpac/gpac/commit/13eb5b76560aaf7813b865a2ad433258478e2695](https://github.com/gpac/gpac/commit/13eb5b76560aaf7813b865a2ad433258478e2695)
- [https://github.com/gpac/gpac/issues/3303](https://github.com/gpac/gpac/issues/3303)

## Related threats

- [GPAC MP4Box heap use-after-free in AC4 descriptor parsing](https://junglewise.ai/threats/cve-2025-60476-a-heap-use-after-free-in-the-gf-odf-ac4-cfg-clean-list-function)
- [GPAC MP4Box NULL pointer dereference in AC4 parser](https://junglewise.ai/threats/cve-2025-60469-a-null-pointer-dereference-in-the-gf-ac4-presentation-ch-mode)
- [GPAC MP4Box null pointer dereference in GetESD](https://junglewise.ai/threats/cve-2025-60497-a-segmentation-violation-in-the-getesd-function-isomedia-track-c)
- [GPAC MP4Box segmentation violation in check_media_profile](https://junglewise.ai/threats/cve-2025-60493-a-segmentation-violation-in-the-check-media-profile-function)
- [GPAC MP4Box stack overflow in BIFS scene decoder](https://junglewise.ai/threats/cve-2025-60492-a-stack-overflow-in-the-gf-bifs-dec-node-function-bifs-field)