CVE-2026-86420 in ImageMagick
Summary
by MITRE • 09/07/2026
ImageMagick before 7.1.2-30 and 6.9.13-55 fails to properly lower the memory budget when an operation inside OpenPixelCache fails. Repeated triggering of such failures can exhaust the process memory budget and result in a denial of service.
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Analysis
by VulDB Data Team • 09/07/2026
The vulnerability identified in ImageMagick versions prior to 7.1.2-30 and 6.9.13-55 represents a critical resource management flaw within the OpenPixelCache subsystem. This component is responsible for managing memory allocation for image processing operations, utilizing a budgeting mechanism designed to prevent excessive memory consumption that could destabilize the host system or application hosting the library. The core technical deficiency lies in the error handling logic associated with this cache; specifically, when an operation initiated within the OpenPixelCache fails, the software does not correctly decrement or adjust the allocated memory budget. This oversight means that resources reserved for a failed task remain locked and unreturned to the available pool, effectively creating a persistent leak of system memory relative to the process's allowed limits.
From a technical perspective, this flaw is categorized under CWE-401, which describes missing release of memory after effective usage, or more broadly as CWE-789 regarding memory leaks that lead to resource exhaustion. The vulnerability exploits the assumption that failed operations will trigger proper cleanup routines similar to successful ones. However, due to the specific implementation details in these older versions, the failure path bypasses the necessary deallocation steps. Consequently, each subsequent attempt to process an image or execute a command that triggers this internal cache error results in additional memory being reserved without corresponding release. This behavior transforms what might appear as isolated processing errors into a systematic degradation of system resources over time.
The operational impact of this vulnerability is primarily centered on denial of service through resource exhaustion. An attacker who can induce repeated failures within the OpenPixelCache mechanism, such as by submitting crafted image files or specific command sequences that trigger internal cache errors, can gradually consume all available memory allocated to the ImageMagick process. As the memory budget is exhausted, the application may become unresponsive, crash, or be terminated by the operating system's out-of-memory killer mechanisms. In environments where ImageMagick is used as a service component for web applications or automated processing pipelines, this can lead to significant downtime and disruption of services that depend on image manipulation capabilities.
This behavior aligns with attack patterns observed in MITRE ATT&CK framework under resource hijacking techniques, specifically those involving memory exhaustion to degrade availability. While the vulnerability does not directly allow for arbitrary code execution or privilege escalation, its potential to disrupt service makes it a high-severity issue in contexts where reliability is paramount. The lack of proper budget adjustment during error states indicates a gap in defensive programming practices regarding resource lifecycle management within the library's core architecture.
To mitigate this risk, organizations utilizing ImageMagick must upgrade immediately to version 7.1.2-30 or later for the v7 branch, and version 6.9.13-55 or later for the legacy v6 branch. These releases contain patches that ensure the memory budget is correctly lowered even when internal operations fail, thereby preventing the accumulation of unreleased resources. Additionally, administrators should implement monitoring solutions to track memory usage patterns in applications relying on ImageMagick, allowing for early detection of anomalous behavior indicative of exploitation attempts. Regular updates and adherence to vendor security advisories remain essential practices for maintaining the integrity and availability of systems dependent on this widely used image processing library.