CVE-2021-20309: Debian Linux

High severity, CVSS 7.5. EPSS: 2.3% chance of exploitation in the next 30 days.

A flaw was found in ImageMagick in versions before 7.0.11 and before 6.9.12, where a division by zero in WaveImage() of MagickCore/visual-effects.c may trigger undefined behavior via a crafted image file submitted to an application using ImageMagick. The highest threat from this vulnerability is to system availability.

Affected products

• Debian Debian Linux: version 9.0 only
• ImageMagick ImageMagick: before 6.9.12 (fixed in 6.9.12); from 7.0.0-0, before 7.0.11-0 (fixed in 7.0.11-0)

Published 2021-05-11. Last modified 2026-06-17.