ImageMagick versions before 7.1.2-31 and 6.9.13-56 contain a use-after-free vulnerability in the ImagesToBlob method due to improper pointer handling. This vulnerability can cause a denial of service by crashing the affected process. The issue is fixed in versions 7.1.2-31 and 6.9.13-56. Ubuntu security advisories confirm fixes are available for affected Ubuntu LTS releases, with updates provided through standard system updates or Ubuntu Pro Extended Security Maintenance (ESM).