CVE-2016-8678 in ImageMagick
Summary
by MITRE
The IsPixelMonochrome function in MagickCore/pixel-accessor.h in ImageMagick 7.0.3.0 allows remote attackers to cause a denial of service (out-of-bounds read and crash) via a crafted file. NOTE: the vendor says "This is a Q64 issue and we do not support Q64."
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Analysis
by VulDB Data Team • 08/27/2025
The vulnerability CVE-2016-8678 represents a critical out-of-bounds read condition affecting ImageMagick's pixel accessor functionality, specifically within the IsPixelMonochrome function located in MagickCore/pixel-accessor.h. This flaw exists in ImageMagick version 7.0.3.0 and enables remote attackers to execute denial of service attacks through carefully crafted malicious files. The vulnerability stems from insufficient input validation and boundary checking within the pixel processing pipeline, where the function fails to properly validate pixel data dimensions before attempting to access memory locations beyond the allocated buffer boundaries.
The technical implementation of this vulnerability involves the IsPixelMonochrome function which is designed to determine whether pixel values represent monochrome data, typically used in image processing operations. When processing malformed input files, the function does not adequately verify the size and structure of pixel data, leading to memory access violations that result in program crashes. This out-of-bounds read occurs because the function assumes certain data structures maintain expected dimensions without proper validation checks. The vulnerability manifests as a segmentation fault or memory corruption that terminates the application process, effectively causing a denial of service condition for legitimate users attempting to process images through the affected software.
From an operational perspective, this vulnerability poses significant risks to systems relying on ImageMagick for image processing tasks, particularly those exposed to untrusted input sources such as web applications, file upload systems, or content management platforms. The remote exploitation capability means that attackers can trigger the vulnerability without requiring local access or authentication, making it particularly dangerous in web-facing environments. The impact extends beyond simple service disruption to potentially enable more sophisticated attacks if combined with other vulnerabilities, as the memory corruption could be leveraged to execute arbitrary code under certain conditions. The vulnerability affects the core image processing capabilities of the software, potentially compromising the integrity of image handling workflows across various applications.
The root cause of this vulnerability aligns with CWE-129, which addresses insufficient validation of length of input buffers, and demonstrates characteristics consistent with ATT&CK technique T1203, specifically "Exploitation for Client Execution" where adversaries exploit software vulnerabilities to execute malicious code. The vendor's statement regarding Q64 support limitations indicates that this issue specifically affects the 64-bit variant of the software, suggesting architectural differences in how pixel data is handled between 32-bit and 64-bit implementations. Organizations should implement immediate mitigations including input validation, sandboxing image processing operations, and updating to patched versions of ImageMagick where available. Additionally, deployment of network intrusion detection systems that can identify malicious file patterns and implementing strict file type validation can help reduce the attack surface. The vulnerability underscores the importance of robust input validation in image processing libraries and highlights the need for comprehensive memory safety practices in multimedia processing software.