Executive brief
MPC-BE is a popular open-source media player for Windows. A vulnerability in how the player processes MP4 video files could allow an attacker to crash the application. To exploit this, an attacker would need to trick a user into opening a specially crafted, malicious video file, resulting in a denial of service.
Technical details
An access violation exists in the CBaseSplitterFile::Read function within MPC-BE's MP4 splitting logic. The vulnerability is triggered when the application attempts to parse a malformed MP4 file containing a crafted AP4_UrlAtom, leading to an invalid memory access (access violation) during a memcpy operation. This issue stems from upstream vulnerabilities in the Bento4 library integrated into MPC-BE. An attacker can achieve a denial of service (application crash) by providing a malicious MP4 file that the user must manually open. The issue was addressed in commit 4341cb3.
Affected products
- Aleksoid1978 MPC-BE before commit 4341cb3
Timeline
- 2026-07-01: disclosed
- 2026-07-01: advisory