CVE-2016-9773 Imagemagick CVE debrief

Who should care

Organizations that process untrusted image files with ImageMagick, especially systems exposing image conversion, upload handling, thumbnails, or batch processing pipelines. Security teams and maintainers should care most if they deploy the affected 7.0.3-8 release or inherited packages built from it.

Technical summary

NVD lists the vulnerable CPE as ImageMagick 7.0.3-8 and assigns CWE-119 and CWE-125. The flaw is in MagickCore/pixel-accessor.h, specifically the IsPixelGray function, where crafted input can trigger an out-of-bounds heap read / heap-based overflow condition. The NVD CVSS vector is CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. The record also states that this vulnerability exists because of an incomplete fix for CVE-2016-9556.

Defensive priority

Medium. The issue is publicly known and affects a specific ImageMagick release, but the published severity is 5.5 and the primary stated outcome is denial of service. Prioritize if the affected version is present in internet-facing or high-volume image-processing workflows.

Recommended defensive actions

• Identify ImageMagick deployments and confirm whether any systems run version 7.0.3-8 or a package derived from it.
• Upgrade to a non-vulnerable ImageMagick release that includes the fix for the incomplete CVE-2016-9556 remediation.
• Treat untrusted image uploads and conversion jobs as security-sensitive inputs and isolate processing where practical.
• Review dependent applications and libraries that bundle or call ImageMagick to ensure they are not shipping the affected code.
• Monitor for crashes or abnormal termination during image parsing or conversion, especially for malformed or user-supplied images.

Evidence notes

The CVE description and NVD metadata identify a heap-based buffer overflow / out-of-bounds heap read in IsPixelGray in MagickCore/pixel-accessor.h, affecting ImageMagick 7.0.3-8. NVD lists CWE-119 and CWE-125, and the record ties the flaw to an incomplete fix for CVE-2016-9556. Reference URLs in the NVD record include Openwall oss-security mailing list posts dated 2016-12-01 and 2016-12-02, plus a Gentoo blog advisory describing the ImageMagick heap-based buffer overflow in IsPixelGray.

Official resources