CVE-2026-56363 Overview
CVE-2026-56363 is a division by zero vulnerability in ImageMagick before version 7.1.2-22. The flaw resides in the binomial kernel processing routine. An attacker who supplies a large binomial kernel value triggers an integer overflow [CWE-190] that ultimately produces a zero divisor. The resulting arithmetic exception crashes the ImageMagick process, causing denial of service on the host running the affected build.
Exploitation requires local access and user interaction, such as processing an attacker-controlled image or kernel argument through an ImageMagick tool or library binding. The issue affects imagemagick distributions bundled with countless image-processing workflows, media pipelines, and web applications.
Critical Impact
A crafted binomial kernel value triggers integer overflow leading to division by zero, crashing ImageMagick and disrupting any service that depends on it for image processing.
Affected Products
- ImageMagick versions prior to 7.1.2-22
- Applications, libraries, and services that embed vulnerable ImageMagick builds
- Linux distributions and container images shipping unpatched ImageMagick packages
Discovery Timeline
- 2026-06-30 - CVE-2026-56363 published to NVD
- 2026-07-02 - Last updated in NVD database
Technical Details for CVE-2026-56363
Vulnerability Analysis
ImageMagick supports morphology operations that build convolution kernels from user-controlled parameters. The binomial kernel path computes coefficient counts and sizes based on the supplied kernel width. When the attacker provides a large binomial value, intermediate arithmetic overflows a fixed-width integer.
The overflow wraps the calculated value to zero. The kernel construction routine then divides another term by that zero value, raising a floating-point or integer divide exception. ImageMagick has no guard against the wrapped result, so the process terminates immediately.
Root Cause
The root cause is missing bounds validation on the binomial kernel size before it participates in size calculations. The vulnerable routine trusts the caller-supplied value and performs multiplication without checking for overflow, matching the CWE-190 integer overflow pattern. Version 7.1.2-22 introduces bounds checks that reject oversized binomial values before arithmetic occurs.
Attack Vector
Exploitation is local and requires user interaction. An attacker crafts a command line, script, or API call that invokes ImageMagick with a large binomial kernel argument, for example through the -morphology Convolve Binomial:<N> option or an equivalent MagickCore API call. When a user or automated workflow processes the input, the ImageMagick process crashes.
The impact is limited to availability. There is no memory corruption, no confidentiality impact, and no path to code execution documented in the advisory. Services that batch-process untrusted images, such as thumbnail generators or upload handlers, are the most exposed because a single crafted job can terminate the worker.
Refer to the GitHub Security Advisory GHSA-vf33-6r7x-66xx and the VulnCheck Advisory for technical details.
Detection Methods for CVE-2026-56363
Indicators of Compromise
- ImageMagick worker processes terminating with SIGFPE (floating-point exception) or arithmetic exception signatures in system logs.
- Repeated crashes of convert, magick, or embedded MagickCore consumers when processing user-supplied inputs.
- Command lines or API calls referencing -morphology with a Binomial kernel and unusually large numeric parameters.
Detection Strategies
- Inventory installed ImageMagick versions across servers and container images and flag any build older than 7.1.2-22.
- Inspect application logs and web request logs for user-supplied kernel arguments feeding into ImageMagick invocations.
- Correlate process-exit telemetry with image-processing job identifiers to identify crash clusters caused by the same input.
Monitoring Recommendations
- Alert on abnormal restart rates for image-processing workers or containers hosting ImageMagick.
- Monitor for spikes in SIGFPE terminations reported by the kernel audit subsystem or container runtime.
- Track ImageMagick package versions through configuration management to detect drift from patched baselines.
How to Mitigate CVE-2026-56363
Immediate Actions Required
- Upgrade ImageMagick to version 7.1.2-22 or later on all systems, including container base images and build pipelines.
- Rebuild and redeploy applications that statically link or vendor MagickCore against the patched release.
- Restrict user-controlled parameters passed to -morphology, -kernel, and related options in application code.
Patch Information
The ImageMagick maintainers released the fix in version 7.1.2-22. Details and patch references are available in the GitHub Security Advisory GHSA-vf33-6r7x-66xx. Downstream Linux distributions publish backported packages through their standard security channels.
Workarounds
- Disable or block ImageMagick features that accept user-controlled kernel definitions where the patched build is not yet deployed.
- Enforce input validation that caps numeric arguments for binomial and other morphology kernels to a safe upper bound.
- Run ImageMagick workers under process supervisors that automatically restart crashed instances to preserve service availability until patching completes.
# Verify installed ImageMagick version and upgrade if vulnerable
magick -version | head -n 1
# Debian/Ubuntu
sudo apt-get update && sudo apt-get install --only-upgrade imagemagick
# RHEL/Fedora
sudo dnf upgrade ImageMagick
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
