CVE-2026-56370: ImageMagick Out-of-Bounds Access in ConnectedComponentsImage()

Technical summary

CVE-2026-56370 is an out-of-bounds read/write vulnerability (CWE-125: Out-of-bounds Read) in ImageMagick's ConnectedComponentsImage() function. The flaw occurs when the function processes connected-components artifacts containing invalid indices. An attacker can craft malicious connected-components definitions and pass them via the ImageMagick command-line interface to trigger an access violation. The vulnerability resides in the artifact processing logic, where bounds checking on array indices is insufficient. Exploitation requires the attacker to control input data—typically through direct CLI invocation or via an application that passes untrusted image metadata to ImageMagick—combined with user interaction. The out-of-bounds condition can result in application termination (DoS) or, depending on memory layout and exploit sophistication, potential code execution.

Business impact

Organizations relying on ImageMagick for automated image processing, batch conversions, or web-based image manipulation services face potential service disruptions if an attacker supplies crafted image files. In web environments, this could be leveraged to disable image processing pipelines or as part of a broader attack. The low CVSS score reflects the requirement for local access and user interaction, but businesses processing user-submitted images should still assess their exposure. For most enterprise deployments where ImageMagick runs in sandboxed or isolated environments, the practical risk is limited to denial of service; however, code execution is theoretically possible and should not be dismissed in high-security contexts.

Affected systems

ImageMagick versions before 7.1.2-19 are affected. This includes all 7.1.2 releases up to and including 7.1.2-18, as well as all earlier stable and development versions. Organizations should verify their exact ImageMagick version (run 'convert -version') to determine exposure. The vulnerability does not affect ImageMagick 7.1.2-19 and later.

Exploitability

Exploitation requires local or authenticated access to invoke ImageMagick with malicious connected-components definitions. An attacker cannot remotely exploit this vulnerability without a prior compromise or trusted relationship. The attack requires user interaction—either direct command-line invocation or triggering the vulnerable code path through an application. This combination of factors results in a low CVSS score (3.3). However, in web service contexts where image uploads are processed automatically by backend services, the barrier to exploitation may be lower, as an attacker can submit a crafted image as an ordinary user. The vulnerability is not known to be actively exploited in the wild.

Remediation

Upgrade ImageMagick to version 7.1.2-19 or later. Before upgrading, verify compatibility with your existing applications and scripts, as ImageMagick updates can occasionally introduce behavioral changes. Test the updated version in a staging environment if image processing is critical to your operations. For organizations unable to patch immediately, consider restricting ImageMagick usage to trusted, authenticated users and disabling or sandboxing any public-facing image upload or processing features.

Patch guidance

Apply the ImageMagick security update to version 7.1.2-19 or later as provided by your distribution or directly from the ImageMagick project. Verify the patch has been applied by running 'convert -version' and confirming the version is 7.1.2-19 or higher. On Linux systems, use your package manager (apt, yum, dnf, etc.) to update imagemagick to the patched version. On Windows and macOS, download the latest binary from the official ImageMagick website and follow the installation instructions. If you maintain custom builds or compile from source, pull the latest code from the official repository or apply the upstream patch. Test image processing workflows post-patch to ensure functionality is preserved.

Detection guidance

Monitor logs for ImageMagick errors or crashes when processing image files, particularly those containing unusual connected-components metadata. If you run ImageMagick as a service, enable core dump capture and examine any segmentation faults or access violations. On systems processing user-submitted images, enable application-level logging to record which images trigger errors. Use file integrity monitoring to detect unexpected binary changes to imagemagick executables. Network-based detection is limited due to the local nature of the vulnerability; focus on endpoint and application monitoring. Consider fuzzing image inputs with malformed connected-components data in a test environment to verify your patching status.

Why prioritize this

While this vulnerability carries a low CVSS score due to its local-access requirement and user-interaction dependency, it should be prioritized for remediation within normal patch cycles. Organizations processing untrusted image data—such as those offering image upload services, automated photo processing, or accepting user-submitted artwork—should elevate this to medium priority. The potential for code execution, albeit difficult to achieve, warrants expedited patching in security-sensitive environments. For internal-only ImageMagick usage, standard patching schedules are sufficient.

Risk score, explained

The CVSS 3.1 score of 3.3 (LOW) reflects: (1) Attack Vector: Local—the attacker must have local or authenticated access; (2) Attack Complexity: Low—no special conditions are required once access is granted; (3) Privileges Required: None—the vulnerability can be triggered by any local user; (4) User Interaction: Required—the vulnerability depends on user action or application logic; (5) Scope: Unchanged—impact is limited to the affected component; (6) Confidentiality: None—no sensitive information is exposed; (7) Integrity: None—the attack does not modify data; (8) Availability: Low—the primary impact is application crash or service disruption. The score appropriately captures the low barrier to triggering the vulnerability once local access is obtained, but acknowledges the requirement for that access in the first place.

Frequently asked questions