CVE-2026-45664: ImageMagick MNG Coder Resource Limit Bypass (CVSS 5.3)

Technical summary

The vulnerability stems from insufficient validation in the MNG coder component. MNG files can contain multiple images, and ImageMagick applies a configurable limit policy to restrict how many images are processed. However, a missing bounds check in the MNG handler allows this limit to be circumvented. An attacker can construct an MNG file containing more images than the policy permits, causing the application to allocate and process more resources than intended. This maps to CWE-400 (Uncontrolled Resource Consumption), CWE-407 (Improper Restriction of Rendered UI Layers or Frames), CWE-674 (Uncontrolled Recursion), and CWE-770 (Allocation of Resources Without Limits or Throttling), reflecting the fundamental nature of the flaw.

Business impact

Organizations relying on ImageMagick for batch image processing, web-based image handling, or automated image conversion pipelines face risk of service disruption. An attacker sending specially crafted MNG files to an ImageMagick-based service could exhaust memory, CPU, or disk resources, degrading availability for legitimate users. For businesses running containerized or resource-constrained environments, this could trigger cascading failures. However, the CVSS 5.3 MEDIUM score reflects the fact that this is a denial-of-service vector with no confidentiality or integrity impact—the threat is operational rather than data-focused.

Affected systems

ImageMagick versions 6.9.13-46 and earlier in the 6.x branch, and versions 7.1.2-21 and earlier in the 7.x branch are vulnerable. Any system or service that processes MNG image files using affected ImageMagick versions is at risk. This includes web applications offering image upload or conversion features, automated image processing pipelines, and containerized services using ImageMagick as a dependency. Organizations should audit their supply chain to identify embedded or indirect use of ImageMagick.

Exploitability

Exploitation requires network access to submit a malicious MNG file to an ImageMagick-based service. No authentication or user interaction is required beyond file submission. The attack vector is straightforward—the attacker needs only to craft a valid MNG file structure with an excessive number of images. However, practical impact depends on the service's configuration: if resource limits are enforced at the container or system level, the effect may be contained. The vulnerability is not known to be actively exploited in the wild at present, and it has not been added to CISA's Known Exploited Vulnerabilities (KEV) catalog.

Remediation

Update ImageMagick to version 6.9.13-47 or later in the 6.x branch, or to version 7.1.2-22 or later in the 7.x branch. Verify the installed version with 'convert -version'. For organizations unable to patch immediately, implement network-level controls to restrict access to ImageMagick services and configure strict resource limits (memory, CPU, timeouts) at the application or container level. Consider disabling MNG file processing if it is not required for your workflows.

Patch guidance

Apply updates through your standard patch management process. For Linux distributions, check if ImageMagick is available via package managers (apt, yum, etc.) and update accordingly. For containerized deployments, rebuild images with patched versions of ImageMagick. Verify patching with 'convert -version' and confirm the reported version matches or exceeds 6.9.13-47 (6.x) or 7.1.2-22 (7.x). Test patched builds in a staging environment to ensure compatibility with existing image processing workflows before production deployment.

Detection guidance

Monitor application and system logs for unusual resource consumption patterns when processing image files. Look for spikes in memory usage, CPU utilization, or I/O activity associated with ImageMagick processes. If feasible, log file sizes and image counts processed; anomalously large MNG files with many embedded images warrant investigation. Web application firewalls can be configured to restrict uploads of oversized or suspicious MNG files. Runtime Application Self-Protection (RASP) solutions can detect and alert on resource exhaustion patterns triggered by specific file types.

Why prioritize this

While the CVSS score is MEDIUM and the vulnerability carries a denial-of-service risk rather than data exposure, prioritization depends on your attack surface. If your organization exposes ImageMagick-based image processing to untrusted external users, this merits prompt patching. If ImageMagick is used only for internal, trusted workflows, risk is lower but still warrants timely remediation. The lack of active exploitation and KEV status suggest this is not an imminent widespread threat, but the ease of exploitation and broad use of ImageMagick justify a measured but deliberate patch timeline.

Risk score, explained

The CVSS 3.1 score of 5.3 (MEDIUM) reflects a network-accessible vulnerability with low complexity and no authentication required, but limited impact scope. The scoring emphasizes availability (denial of service) with no confidentiality or integrity components. The absence of user interaction and the straightforward attack vector push the score upward, but the constraint to denial of service—rather than remote code execution or data exfiltration—prevents a higher rating. Organizations should assess their own risk by considering the criticality of affected services and the trustworthiness of file sources.

Frequently asked questions