CVE-2021-21842: Debian Linux

High severity, CVSS 8.8. EPSS: 1.7% chance of exploitation in the next 30 days.

An exploitable integer overflow vulnerability exists within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. A specially crafted MPEG-4 input can cause an integer overflow when processing an atom using the 'ssix' FOURCC code, due to unchecked arithmetic resulting in a heap-based buffer overflow that causes memory corruption. An attacker can convince a user to open a video to trigger this vulnerability.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only
• Gpac Gpac: version 1.0.1 only

Published 2021-08-25. Last modified 2026-06-17.