# CVE-2026-36912: Aleksoid1978 MPC-BE NULL pointer dereference in AP4_AtomSampleTable

Source: https://junglewise.ai/threats/cve-2026-36912-aleksoid1978-mpc-be-null-pointer-dereference-in-ap4  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-01. Updated: 2026-07-01  
License: CC BY 4.0 with a link back

CVE-2026-36912 · Severity: info · CVSS 5.5 · Published 2026-07-01

Aleksoid1978 MPC-BE, a popular open-source media player for Windows, is vulnerable to a crash when processing specifically malformed video files. An attacker could share a specially crafted MP4 file that, when opened by a user, causes the application to stop responding or crash entirely. This disrupts the user's ability to use the software but does not typically lead to data theft.

Technologies: [Aleksoid1978 MPC-BE](https://junglewise.ai/threats/technologies/mpc-be). Vendors: [Aleksoid1978](https://junglewise.ai/threats/vendors/aleksoid1978).

## Quick answers

**Is CVE-2026-36912 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-36912 being exploited in the wild.

**How severe is CVE-2026-36912?** Informational severity, with a CVSS score of 5.5, published 1 July 2026.

**Which products and versions are affected?** Aleksoid1978 MPC-BE before commit 4341cb3.

**Is there a fix for CVE-2026-36912?** 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-2026-36912 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-36912?** Check whether you run Aleksoid1978 MPC-BE 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

A NULL pointer dereference exists in the AP4_AtomSampleTable::GetSample() function within the Bento4 library integration of Aleksoid1978 MPC-BE. The vulnerability is triggered when the application attempts to process a malformed MP4 file containing inconsistent sample table atoms, specifically within the AP4_Stz2Atom::GetSampleSize logic. An attacker can exploit this by providing a crafted MP4 file that leads to a memory access violation (SEGV) on the zero page. This results in a local denial-of-service (application crash). The issue was addressed in commit 4341cb3.

## Affected products

- Aleksoid1978 MPC-BE before commit 4341cb3

## Timeline

- 2020-05-16: disclosed: Initial discovery in underlying Bento4 library reported
- 2026-07-01: advisory: CVE published by NVD/MITRE

## References

- [https://github.com/Aleksoid1978/MPC-BE/issues/1062](https://github.com/Aleksoid1978/MPC-BE/issues/1062)
- [https://github.com/axiomatic-systems/Bento4/issues/511](https://github.com/axiomatic-systems/Bento4/issues/511)

## Related threats

- [Aleksoid1978 MPC-BE division by zero in CStreamSwitcherOutputPin](https://junglewise.ai/threats/cve-2026-36911-aleksoid1978-mpc-be-division-by-zero-in-cstreamswitcheroutputpin)
- [Aleksoid1978 MPC-BE access violation in BaseSplitterFile::Read](https://junglewise.ai/threats/cve-2026-36910-aleksoid1978-mpc-be-access-violation-in-basesplitterfile-read)
- [Aleksoid1978 MPC-BE NULL pointer dereference in AP4_TkhdAtom::GetTrackId](https://junglewise.ai/threats/cve-2026-36909-aleksoid1978-mpc-be-null-pointer-dereference-in-ap4-tkhdatom)