CVE-2026-93588 in ImageMagick
Summary
by MITRE • 09/18/2026
ImageMagick before 7.1.2-31 and before 6.9.13-56 contains a NULL pointer dereference in the PNM coder. When the coder reaches a memory (resource) limit at a specific point during processing, the failed allocation is not handled and a NULL pointer is dereferenced, which can lead to a denial of service (application crash) when processing a specially crafted or sufficiently large PNM image.
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified in ImageMagick versions prior to 7.1.2-31 and 6.9.13-56 represents a critical memory management flaw within the Portable Any Map, commonly known as PNM, coder module. This component is responsible for parsing and processing image files formatted according to the PBM, PGM, or PPM standards. The core technical deficiency lies in the error handling logic during resource allocation operations. Specifically, when ImageMagick attempts to allocate memory buffers required for decoding a PNM file, it relies on standard system calls that may fail if the requested size exceeds available resources or hits internal limits imposed by the library's configuration. In vulnerable versions of the software, these allocation failures are not adequately checked before proceeding with subsequent operations. Consequently, when an allocation request fails and returns a NULL pointer instead of a valid memory address, the application continues execution under the false assumption that the buffer was successfully allocated.
This lack of defensive programming leads directly to a null pointer dereference exception. As the processing pipeline attempts to write data into or read from this non-existent memory location, it triggers an access violation within the operating system's protected memory space. For local users executing ImageMagick commands on untrusted input files, such as those generated by malicious actors, this results in an immediate application crash. The severity of this issue is compounded by its potential for remote exploitation if ImageMagick is deployed as part of a web service or automated pipeline that processes user-uploaded images without sufficient sandboxing or resource limits. An attacker can craft a PNM file with specific dimensions and color depth parameters designed to exhaust memory resources at the precise moment of allocation, thereby guaranteeing the failure condition required to trigger the crash.
From an operational perspective, this vulnerability primarily impacts availability rather than confidentiality or integrity in its direct manifestation. The denial of service effect disrupts any workflow dependent on ImageMagick for image processing, potentially causing downtime for web applications that rely on dynamic thumbnail generation or format conversion services. While a simple application crash is the immediate outcome, such memory corruption bugs can sometimes serve as stepping stones for more severe exploits if the surrounding context allows for further manipulation of control flow data, although in this specific case, the primary risk remains service disruption. The flaw aligns with CWE-476, which describes NULL Pointer Dereference vulnerabilities arising from improper handling of return values from memory allocation functions. It also relates to CWE-20 regarding Improper Input Validation, as the system fails to validate that resources were successfully acquired before use.
Mitigation strategies for this vulnerability involve immediate software updates and architectural hardening. The most effective remediation is upgrading ImageMagick to version 7.1.2-31 or later, or version 6.9.13-56 and above, where the developers have implemented proper checks for NULL pointers following memory allocation calls within the PNM coder. Organizations should also enforce strict resource limits using system-level controls such as ulimit on Unix-like systems to prevent any single process from consuming excessive memory that could trigger these edge cases. Additionally, deploying ImageMagick behind a reverse proxy or in a containerized environment with limited CPU and memory quotas can mitigate the impact of denial-of-service attempts by isolating failures and preventing them from affecting host system stability. Regular auditing of image processing pipelines to ensure they handle malformed inputs gracefully is also recommended as part of a broader security posture aligned with MITRE ATT&CK techniques related to resource exhaustion, such as T1496 Resource Hijacking or general denial-of-service vectors like T1499 Endpoint Denial of Service.