CVE-2026-109281 in ImageMagick
Summary
by MITRE • 10/12/2026
ImageMagick 7.1.0-21 before 7.1.2-32 contains a heap buffer over-read in its handling of the -fx option, where a certain -fx operation reads beyond the bounds of an allocated heap buffer in specific situations. Attackers who can get a crafted -fx expression processed can read out-of-bounds heap memory, potentially disclosing limited memory contents.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in ImageMagick versions 7.1.0-21 through 7.1.2-32 represents a critical security flaw within the image processing engine's handling of the -fx option. This component allows users to apply complex mathematical expressions and pixel manipulation functions directly via command-line arguments or configuration files. The core technical deficiency is classified as a heap buffer over-read, which occurs when the software attempts to access memory locations that lie outside the boundaries of an allocated heap buffer. Specifically, during the evaluation of certain -fx operations, the parser fails to correctly validate array indices or pointer offsets before dereferencing them. This logical error results in the program reading data from adjacent memory regions that were not intended for this specific operation, thereby violating the fundamental principle of memory safety.
From a technical perspective, heap buffer over-reads are particularly dangerous because they do not typically cause immediate application crashes like stack-based issues might. Instead, they allow an attacker to silently extract sensitive information stored in nearby memory blocks. In the context of ImageMagick, which is often deployed as part of larger web applications or backend services that process user-uploaded images, this vulnerability can be triggered remotely if the service accepts untrusted input for image processing parameters. The exploitation does not require code execution privileges on the target system but rather relies on the ability to submit a crafted -fx expression that triggers the out-of-bounds read condition. This makes it a viable vector for information disclosure attacks where an attacker can gradually reconstruct sensitive data from the server's memory space, such as authentication tokens, private keys, or other application-specific secrets.
The operational impact of this vulnerability is significant due to the widespread adoption of ImageMagick across various industries including e-commerce, media publishing, and government services that rely on automated image resizing, format conversion, or thumbnail generation. An attacker leveraging this flaw can perform a non-intrusive reconnaissance activity by reading arbitrary memory contents. While the disclosure might be limited in scope depending on what resides adjacent to the allocated buffer in memory at runtime, even partial data leakage can compromise system integrity and confidentiality. This aligns with CWE-125, which defines out-of-bounds read vulnerabilities as a category of errors where software reads past the end of an allocated region of memory. Such flaws undermine the trustworthiness of image processing pipelines and can lead to secondary attacks if sensitive credentials are exposed.
To mitigate this risk, organizations utilizing ImageMagick must immediately upgrade to version 7.1.2-32 or later, which contains patches addressing these boundary validation checks within the -fx expression evaluator. For environments where upgrading is not immediately feasible, implementing strict input sanitization and restricting the use of complex mathematical expressions in image processing workflows can reduce exposure. Additionally, deploying Web Application Firewalls with rules capable of detecting anomalous patterns in command-line arguments or configuration files may provide a layer of defense against exploitation attempts. Security teams should also monitor for unusual memory access patterns or unexpected data exfiltration indicators that could signal active probing for this vulnerability. This incident underscores the importance of rigorous code review practices and static analysis tools to detect buffer boundary errors before deployment, ensuring compliance with secure coding standards such as those outlined in OWASP guidelines for input validation and error handling.