CVE-2026-56374: ImageMagick FTXT Heap Buffer Overflow (Low Severity)

Technical summary

CVE-2026-56374 is a heap buffer overflow (CWE-125) in ImageMagick's FTXT encoder stemming from inadequate boundary validation during ftxt:format parsing. The vulnerability permits out-of-bounds memory reads, which can manifest as either application crashes (denial of service) or information leaks depending on memory layout and attacker intent. The affected code path is triggered when ImageMagick attempts to process a crafted FTXT image without proper input sanitization. Exploitation requires local access and user action to process the malicious file.

Business impact

Organizations relying on ImageMagick for image processing workflows face potential service disruption if an employee or automated system processes a malicious FTXT file. The risk is primarily availability-focused (denial of service) rather than confidentiality or integrity. However, in environments where ImageMagick processes untrusted or user-supplied images, information disclosure becomes a secondary concern. The low CVSS score (3.3) reflects the requirement for local access and user interaction, but the impact should be evaluated against how your organization handles untrusted image files.

Affected systems

ImageMagick installations prior to version 7.1.2-19 are affected. This includes systems where ImageMagick is used for batch image conversion, web-based image processing backends, content management systems with image upload functionality, or security tools that analyze image files. The vulnerability does not affect systems using patched versions 7.1.2-19 or later.

Exploitability

Exploitation requires local system access combined with user action to process a malicious FTXT file. An attacker cannot remotely trigger this vulnerability through network mechanisms alone. The attack surface is confined to scenarios where untrusted FTXT images can reach an ImageMagick instance—for example, user-uploaded images to a web application, email attachments processed by automated systems, or files shared on network drives. The barrier to exploitation is low once a malicious file reaches the target system, but distribution and social engineering are necessary prerequisites.

Remediation

Upgrade ImageMagick to version 7.1.2-19 or later. Organizations should prioritize patching systems that process user-supplied or untrusted images. In the interim, consider restricting FTXT file processing or implementing file-type validation to reject unexpected image formats. Web applications should enforce strict image format whitelisting and validate uploaded files server-side before passing them to ImageMagick.

Patch guidance

Apply ImageMagick version 7.1.2-19 or later according to your deployment model. For package-managed systems (Linux distributions), check your package repository for availability and apply updates through your standard patch management process. For containerized deployments, rebuild images with the patched ImageMagick version. For source-compiled installations, download and compile version 7.1.2-19 or later from the official ImageMagick repository. Verify the patch by confirming version output after deployment.

Detection guidance

Monitor for ImageMagick process crashes or unexpected terminations, particularly if they correlate with FTXT file processing or unusual image file handling. Log file analysis of systems processing images should flag any segmentation faults or memory access violations. Endpoint detection and response (EDR) tools can identify abnormal ImageMagick process behavior. Additionally, audit your environment to identify which systems have ImageMagick installed and which are processing user-supplied images, then prioritize patching those assets accordingly.

Why prioritize this

While the CVSS score is low (3.3), the prioritization should reflect your organization's exposure. Patch this vulnerability for systems that handle untrusted image files or user uploads—these represent genuine attack vectors. Systems using ImageMagick only for controlled, internal image processing may be lower priority. The lack of KEV (Known Exploited Vulnerabilities) status suggests limited active exploitation, but the simplicity of triggering a denial-of-service condition means opportunistic attackers could target vulnerable installations if given the chance.

Risk score, explained

The CVSS 3.1 score of 3.3 (LOW) reflects a vulnerability with local attack vector, low complexity, no privilege requirement, user interaction needed, and limited scope. The impact is confined to availability (denial of service) with no direct confidentiality or integrity compromise under typical circumstances. However, information disclosure remains possible depending on memory state. Organizations with high availability requirements or those processing user-supplied images should treat this as higher priority than the score alone suggests.

Frequently asked questions