# CVE-2026-36911: Aleksoid1978 MPC-BE division by zero in CStreamSwitcherOutputPin

Source: https://junglewise.ai/threats/cve-2026-36911-aleksoid1978-mpc-be-division-by-zero-in-cstreamswitcheroutputpin  
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-2026-36911 · Severity: info · CVSS 0 · Published 2026-07-01

Aleksoid1978 MPC-BE is a popular open-source media player for Windows. A vulnerability in how the player handles specific video stream data allows an attacker to crash the application by providing a specially crafted MP4 file. This could lead to a denial-of-service, preventing users from playing media or causing the application to become unresponsive.

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

## Quick answers

**Is CVE-2026-36911 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-36911 being exploited in the wild.

**How severe is CVE-2026-36911?** Informational severity, with a CVSS score of 0, published 1 July 2026.

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

**Is there a fix for CVE-2026-36911?** 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-2026-36911 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-36911?** 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 division-by-zero vulnerability exists in the CStreamSwitcherOutputPin::DecideBufferSize function of MPC-BE. The flaw is triggered when the application processes a malformed MP4 file that contains unexpected values in the stream metadata, leading to an unhandled arithmetic exception. An attacker can exploit this by tricking a user into opening a crafted MP4 file, resulting in an immediate application crash (Denial of Service). The issue was addressed in commit 4341cb3.

## Affected products

- Aleksoid1978 MPC-BE (Media Player Classic Black Edition) before commit 4341cb3

## Timeline

- 2026-07-01: advisory: CVE-2026-36911 published
- 2026-07-01: disclosed

## References

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

## Related threats

- [Aleksoid1978 MPC-BE NULL pointer dereference in AP4_AtomSampleTable](https://junglewise.ai/threats/cve-2026-36912-aleksoid1978-mpc-be-null-pointer-dereference-in-ap4)
- [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)