CVE-2026-55595: ImageMagick Infinite Loop Denial-of-Service Vulnerability

Technical summary

The vulnerability stems from improper input validation in ImageMagick's connected-components image processing option. When invalid arguments are passed to this feature, the application fails to detect the malformed input and enters an infinite loop rather than rejecting or gracefully handling the bad parameters. This is classified under CWE-400 (Uncontrolled Resource Consumption) and CWE-835 (Infinite Loop), indicating the root cause involves resource exhaustion through control flow failure. The flaw requires local access and user interaction (a user must supply or process the malicious input), which constrains the attack surface but does not eliminate risk in environments where untrusted images or commands are processed.

Business impact

For organizations running ImageMagick—including web applications, content management systems, and automated image processing pipelines—this vulnerability enables a denial-of-service condition. An attacker who can supply input to an ImageMagick process can hang it indefinitely, disrupting batch image processing jobs, stalling web requests, or consuming system resources until manual intervention occurs. In production environments handling user-uploaded images, the impact is particularly acute, as a single malicious upload could disable image processing for all subsequent requests. Service availability, rather than data confidentiality or integrity, is the primary concern.

Affected systems

ImageMagick versions prior to 6.9.13-51 and 7.1.2-26 are affected. Both the legacy 6.x and current 7.x branches have fixed versions available. Any system or application embedding or calling ImageMagick for image manipulation is potentially vulnerable if running an older version. This includes Linux distributions packaging ImageMagick, container images, and applications distributed with bundled ImageMagick binaries. Server and desktop environments that accept user-supplied images are at greatest risk.

Exploitability

Exploitability is moderate but practical. The attack requires local access or the ability to supply input to an ImageMagick process (e.g., by uploading an image to a web service that processes it). No authentication bypass or network propagation is involved. An attacker must know or discover that the connected-components option is in use and craft input that triggers the infinite loop—a relatively low bar given that the flaw occurs on invalid input, which is easier to identify than logic-dependent bugs. The CVSS score of 4.7 (Medium) reflects the combination of low attack complexity, local/user-interaction requirement, and high availability impact.

Remediation

Upgrade ImageMagick immediately: users on the 6.x line should update to version 6.9.13-51 or later; users on 7.x should update to 7.1.2-26 or later. Verify against the vendor advisory to confirm the exact version numbering and patch availability for your distribution or deployment method. As an interim mitigation, if upgrading is not immediately possible, restrict user-supplied input to ImageMagick (e.g., disable or remove the connected-components option from available commands, use sandboxing or resource limits to terminate hung processes after a timeout, and avoid processing untrusted image files with vulnerable versions).

Patch guidance

Patches are available in ImageMagick 6.9.13-51 (6.x series) and 7.1.2-26 (7.x series). Check your current version using `convert -version` or `magick -version`. If you are on the 6.x branch and the version is lower than 6.9.13-51, update immediately. If on 7.x and below 7.1.2-26, update to the fixed version. Package managers (apt, yum, brew, etc.) will likely offer the patched version; verify the version number in the repository before installing. For containerized deployments, rebuild images with the patched ImageMagick version and redeploy. Applications that bundle ImageMagick must be updated by the vendor or recompiled against the patched library.

Detection guidance

Monitor for processes becoming unresponsive or consuming high CPU time indefinitely when processing images. Check application logs for calls to connected-components or image processing operations that do not complete. Set resource limits (ulimit, cgroups) on ImageMagick processes to enforce timeout-based termination. Use process monitoring tools to alert on hung ImageMagick instances. Network-level detection is difficult; focus on endpoint and application-level signals. If you suspect exposure, scan your environment for ImageMagick versions using vulnerability scanners or package managers to identify instances below 6.9.13-51 or 7.1.2-26.

Why prioritize this

This vulnerability warrants prompt but not emergency attention. The CVSS score of 4.7 places it in the medium-severity band, and the requirement for local access or user interaction limits the attack surface. However, organizations that accept user-supplied images or run automated image processing should prioritize patching within 1–2 weeks. The denial-of-service impact, while not as severe as remote code execution, still affects availability and can degrade user-facing services. Service interruption and operational disruption make this a business continuity concern even if data is not at risk.

Risk score, explained

The CVSS 3.1 score of 4.7 (Medium) derives from the following factors: Attack Vector (Local) and low Attack Complexity indicate the flaw is somewhat constrained to local exploitation or user interaction; Privileges Required (None) and User Interaction (Required) mean no special access is needed but user involvement (supplying input) is necessary; Confidentiality, Integrity, and Availability impacts reflect that only Availability is harmed (high impact), while CIA remains unaffected. The vector (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H) captures an availability-only denial-of-service scenario with some friction in attack execution.

Frequently asked questions