CVE-2021-20176: 
ImageMagick vulnerability analysis and mitigation

A divide-by-zero vulnerability (CVE-2021-20176) was discovered in ImageMagick versions 6.9.11-57 and 7.0.10-57, specifically in the gem.c file. The vulnerability was discovered in December 2020 and publicly disclosed in February 2021. This security flaw affects the ImageMagick image processing software suite, which is widely used for editing and manipulating digital images (NVD, MITRE).

The vulnerability exists in the gem.c file of ImageMagick, where a divide-by-zero condition can be triggered when processing specially crafted image files. The flaw has been assigned a CVSS v3.1 base score of 5.5 (Medium), with the vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. The vulnerability is classified under CWE-369 (Divide By Zero) (NVD).

When exploited, this vulnerability allows an attacker to trigger undefined behavior through a division by zero operation, primarily affecting system availability. The main impact is potential application crashes or denial of service conditions, though other undefined behaviors might occur. The highest threat from this vulnerability is to system availability (NVD).

The vulnerability has been fixed in subsequent versions of ImageMagick. Patches were provided through commits in both ImageMagick and ImageMagick6 repositories. Various Linux distributions have released security updates to address this vulnerability, including Debian and Ubuntu (Red Hat Bugzilla, Debian Security).