CVE-2020-22031: 
Ffmpeg vulnerability analysis and mitigation

A Heap-based Buffer Overflow vulnerability was discovered in FFmpeg 4.2, specifically in the filter16_complex_low function within libavfilter/vf_w3fdif.c. The vulnerability was disclosed on May 27, 2021, affecting FFmpeg version 4.2 and its implementation in various Linux distributions (NVD, Ubuntu).

The vulnerability exists in the filter16_complex_low function of the w3fdif filter implementation. When processing video frames, the function performs an out-of-bounds read of size 2 at an address located 32 bytes to the left of an allocated 1055-byte region, leading to a heap-buffer-overflow condition. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (High), with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (FFmpeg Ticket, NVD).

The heap buffer overflow vulnerability could lead to memory corruption and other potential consequences, including possible arbitrary code execution, information disclosure, or denial of service when processing specially crafted input (Debian LTS).

The vulnerability can be triggered when processing video content through the w3fdif filter. A proof of concept has been documented that demonstrates the buffer overflow can be reliably triggered using specific video processing parameters (FFmpeg Ticket).

The vulnerability has been fixed in various distribution releases. Ubuntu has released fixes for versions 20.04 LTS (7:4.2.7-0ubuntu0.1), 18.04 LTS (7:3.4.11-0ubuntu0.1), and 16.04 LTS (7:2.8.17-0ubuntu0.1+esm2). Debian has addressed the issue in version 7:4.1.8-0+deb10u1 for the oldstable distribution (buster) (Debian Security, Ubuntu Security).