CVE-2026-93590 in ImageMagick
Summary
by MITRE • 09/18/2026
ImageMagick before 7.1.2-31 contains a policy bypass vulnerability in the UHDR encoder that fails to perform policy checks during buffer allocation for image pixels. Attackers can bypass resource policies by processing specially crafted UHDR images, potentially causing denial of service through excessive memory allocation.
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Analysis
by VulDB Data Team • 09/18/2026
The identified vulnerability resides within the Universal High Dynamic Range (UHDR) encoding module of ImageMagick versions prior to 7.1.2-31. This component is responsible for handling image formats that utilize high dynamic range data, a critical feature in modern digital imaging workflows involving professional photography and video production. The core technical flaw stems from an incomplete implementation of security policies during the buffer allocation phase specifically tied to pixel data processing. When ImageMagick processes a UHDR image file, it must allocate memory buffers sufficient to hold the raw pixel information before applying any transformations or encodings. In this specific code path, the software fails to validate whether the requested buffer size aligns with the configured resource limits defined in its policy.xml configuration file. This oversight allows an attacker who can supply a maliciously crafted UHDR image to trigger memory allocations that exceed the intended boundaries set by system administrators or default security policies.
From a technical perspective, this flaw represents a classic instance of improper input validation leading to excessive resource consumption. The vulnerability is categorized under CWE-787: Out-of-bounds Write and more specifically aligns with CWE-400: Uncontrolled Resource Consumption because the primary impact observed is related to memory exhaustion rather than arbitrary code execution in most scenarios, although out-of-bounds writes could theoretically occur if heap corruption results from the malformed allocation. The absence of policy checks during this critical initialization step means that the application trusts the dimensions and metadata embedded within the image file without cross-referencing them against established security constraints. This design flaw effectively neutralizes one of ImageMagick's primary defense mechanisms, which is designed to prevent abuse by limiting CPU time, memory usage, disk space, and other resources during image processing operations.
The operational impact of this vulnerability is predominantly centered on denial of service conditions. By crafting a UHDR file with exaggerated dimensions or complex pixel data structures that trigger massive buffer allocations, an attacker can force the ImageMagick process to consume excessive amounts of system memory. This rapid depletion of available RAM can lead to the termination of the processing application by the operating system's out-of-memory killer, causing service disruption for legitimate users. In environments where ImageMagick is deployed as part of a web-based image processing pipeline or an automated content management system, this vulnerability could be exploited remotely via HTTP requests that upload malicious images. The resulting instability can cascade into broader infrastructure issues if multiple concurrent attacks are launched against the affected services, leading to significant downtime and potential data loss due to interrupted processes.
This behavior is consistent with attack patterns documented in the MITRE ATT&CK framework under T1496: Resource Hijacking, where adversaries leverage compromised or vulnerable systems to consume resources for denial of service purposes. It also reflects historical weaknesses seen in other multimedia libraries such as FFmpeg and GD Library, highlighting a common challenge in handling complex binary formats with variable-sized data structures. The lack of pre-allocation validation is particularly dangerous because it allows the vulnerability to be triggered before any significant computational work begins, making detection by runtime monitoring tools more difficult until memory pressure becomes critical.
To mitigate this risk, organizations relying on ImageMagick must immediately upgrade to version 7.1.2-31 or later, where the policy checks have been properly integrated into the UHDR encoder's buffer allocation logic. Administrators should also review their policy.xml configurations to ensure that resource limits such as memory-map and disk-space are set appropriately for their specific use cases. Implementing strict input validation at the application layer before passing files to ImageMagick can provide an additional defense-in-depth strategy. Furthermore, deploying network-level protections or web application firewalls that inspect uploaded image metadata for anomalies in dimensions or file structure can help block malicious payloads before they reach the vulnerable library components. Regular auditing of third-party dependencies and staying informed about security advisories related to multimedia processing libraries are essential practices for maintaining robust cybersecurity hygiene in environments handling user-generated content.