CVE-2016-6823 in ImageMagick
Summary
by MITRE
Integer overflow in the BMP coder in ImageMagick before 7.0.2-10 allows remote attackers to cause a denial of service (crash) via crafted height and width values, which triggers an out-of-bounds write.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2016-6823 represents a critical integer overflow flaw within ImageMagick's BMP coder component, affecting versions prior to 7.0.2-10. This issue manifests when processing specially crafted bitmap image files with manipulated height and width parameters, creating conditions that lead to memory corruption and system instability. The vulnerability resides in the image processing pipeline where ImageMagick fails to properly validate input dimensions before allocating memory for image data structures, creating a scenario where mathematical operations result in integer overflow conditions.
The technical implementation of this vulnerability exploits the fundamental weakness in how ImageMagick handles image dimension calculations during BMP file parsing. When attackers provide malicious height and width values that, when processed through the coder's internal arithmetic operations, exceed the maximum representable value for the integer data type being used, the system experiences integer overflow. This overflow condition causes subsequent memory allocation operations to request buffers that are significantly smaller than required, leading to out-of-bounds write operations when the image data is subsequently written to memory locations beyond the allocated buffer boundaries.
From an operational impact perspective, this vulnerability enables remote attackers to execute successful denial of service attacks against systems running vulnerable versions of ImageMagick. The crash occurs during the image processing phase when the application attempts to write data beyond allocated memory segments, causing the application to terminate abruptly or behave unpredictably. This affects web applications, content management systems, and any software platforms that utilize ImageMagick for image processing, potentially allowing attackers to disrupt services or cause system instability through carefully crafted image uploads or processing requests.
The vulnerability maps directly to CWE-190, Integer Overflow or Wraparound, which specifically addresses situations where arithmetic operations produce results that exceed the maximum value that can be represented by the data type. Additionally, this flaw aligns with ATT&CK technique T1203, Exploitation for Client Execution, as it enables remote code execution through client-side image processing vulnerabilities. The attack surface extends to any application or service that accepts user-uploaded images and processes them through ImageMagick's image handling libraries, making it particularly dangerous in web environments where untrusted image files are commonly processed.
Mitigation strategies for CVE-2016-6823 focus primarily on upgrading to ImageMagick version 7.0.2-10 or later, which includes patches addressing the integer overflow conditions in the BMP coder. System administrators should implement comprehensive input validation measures, including strict parameter validation for image dimensions and size constraints, to prevent malicious inputs from reaching the vulnerable processing components. Network-level protections such as content filtering and image sanitization proxies can provide additional defense-in-depth layers. Organizations should also consider implementing application whitelisting, restricting ImageMagick usage to trusted applications only, and monitoring for unusual processing patterns that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should include checks for ImageMagick installations to ensure all systems remain patched against this and related vulnerabilities.