CVE-2020-12284: 
Ffmpeg vulnerability analysis and mitigation

CVE-2020-12284 is a heap-based buffer overflow vulnerability discovered in FFmpeg versions 4.1 and 4.2.2. The vulnerability exists in the cbs_jpeg_split_fragment function within libavcodec/cbs_jpeg.c during JPEG_MARKER_SOS handling due to a missing length check. The vulnerability was disclosed on April 28, 2020, affecting the FFmpeg multimedia framework (NVD, MITRE).

The vulnerability occurs in the JPEG marker handling functionality of FFmpeg, specifically during the processing of Start of Scan (SOS) markers. The issue stems from a missing length validation check in the cbs_jpeg_split_fragment function, which could lead to a heap-based buffer overflow. The vulnerability has been assigned a CVSS v3.1 base score of 9.8 (Critical), indicating high severity across confidentiality, integrity, and availability impacts (Ubuntu).

If exploited, this vulnerability could allow an attacker to obtain sensitive information or cause other unspecified impacts through specially crafted JPEG files. The vulnerability particularly affected Ubuntu 20.04 LTS systems (Ubuntu Notice).

The vulnerability can be triggered by processing specially crafted JPEG files. The issue was initially discovered through the continuous fuzzing process by OSS-Fuzz (FFmpeg Commit).

The vulnerability has been fixed in FFmpeg version 4.2.4. Users are advised to upgrade to this version or later. For Ubuntu 20.04 LTS users, the fix is available in version 7:4.2.4-1ubuntu0.1. For Debian users, the fix is included in version 7:4.1.6-1~deb10u1 (Debian Security, Ubuntu Notice).