# CVE-2026-88376: Bento4 integer underflow in avcC/hvcC atom parsing

Source: https://junglewise.ai/threats/cve-2026-88376-bento4-1-6-0-0-contains-an-integer-underflow-vulnerability-in-ap4  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-24. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-88376 · Severity: high · CVSS 7.5 · Published 2026-09-24

Bento4 is a multimedia framework used to read, parse, and manipulate MP4 video files. A flaw in the library allows a specially crafted MP4 file to trigger an integer underflow when parsing video codec configuration atoms, causing the application to crash and become unavailable. This can be exploited remotely by sending a malicious MP4 file to any application using Bento4 to process video.

Technologies: [Axiomatic Systems Bento4](https://junglewise.ai/threats/technologies/bento4). Vendors: [Axiomatic Systems](https://junglewise.ai/threats/vendors/axiomatic-systems).

## Quick answers

**Is CVE-2026-88376 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-88376 being exploited in the wild.

**How severe is CVE-2026-88376?** High severity, with a CVSS score of 7.5, published 24 September 2026.

**Which products and versions are affected?** Axiomatic Systems Bento4 1.6.0.0.

**Is there a fix for CVE-2026-88376?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-88376 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-88376?** Check whether you run Axiomatic Systems Bento4 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.

## Technical details

An integer underflow in AP4_AvccAtom::Create() and AP4_HvccAtom::Create() occurs when parsing avcC or hvcC atoms with a declared size smaller than the 8-byte atom header. The payload_size calculation (size - AP4_ATOM_HEADER_SIZE) wraps to a large unsigned value without validation, leading to oversized buffer allocation and out-of-bounds memory operations. This causes application termination via SIGILL, resulting in denial of service; no memory disclosure or code execution is achieved through this path.

## Affected products

- Axiomatic Systems Bento4 1.6.0.0

## Timeline

- 2026-09-24: disclosed: CVE-2026-88376 published

## References

- [https://github.com/axiomatic-systems/Bento4/issues/1091](https://github.com/axiomatic-systems/Bento4/issues/1091)

## Related threats

- [Bento4 integer underflow in MP4 atom parsing](https://junglewise.ai/threats/cve-2026-88377-bento4-1-6-0-0-contains-an-integer-underflow-vulnerability-in-the)
- [axiomatic-systems Bento4 stack overflow in AP4_TrunAtom](https://junglewise.ai/threats/cve-2026-36908-axiomatic-systems-bento4-stack-overflow-in-ap4-trunatom)
- [Axiomatic-systems Bento4 stack overflow in AP4_StsdAtom](https://junglewise.ai/threats/cve-2026-36907-axiomatic-systems-bento4-stack-overflow-in-ap4-stsdatom)