CVE-2026-116146 in ImageMagick
Summary
by MITRE • 10/25/2026
ImageMagick before 6.9.13-58 and 7.x before 7.1.2-33 contains a memory leak in the MSL decoder that fails to release allocated memory when processing a crafted MSL image. Attackers can supply crafted MSL files for processing to repeatedly leak memory, causing resource exhaustion and denial of service.
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Analysis
by VulDB Data Team • 10/25/2026
The vulnerability identified in ImageMagick versions prior to 6.9.13-58 and 7.x before 7.1.2-33 represents a critical flaw within the Markupup Script Language decoder component. This specific subsystem is responsible for interpreting MSL files, which are XML-based documents used by ImageMagick to define complex image processing operations such as compositing, filtering, and geometric transformations. The core technical deficiency lies in the memory management routines of this decoder, specifically where allocated heap memory fails to be properly deallocated after a crafted MSL file is processed. This oversight results in a classic resource leak scenario where each invocation of the vulnerable code path consumes additional system resources without returning them to the operating system or application pool for reuse.
From a technical perspective, this flaw aligns with CWE-401, which describes missing release of memory after effective usage. The vulnerability is triggered when an attacker supplies a specially crafted MSL file designed to exploit specific parsing paths within the decoder that do not include corresponding free calls for allocated buffers. Because ImageMagick is frequently deployed as part of larger web applications or backend services that process user-uploaded images, this flaw can be exploited remotely if the application processes untrusted input without adequate sanitization or resource limits. The attacker does not need to execute arbitrary code but rather needs only to induce repeated processing of these malformed files to accumulate memory leaks over time.
The operational impact of this vulnerability is primarily centered on denial of service through resource exhaustion. As the vulnerable process continues to handle malicious MSL inputs, its resident set size grows indefinitely until it consumes all available system memory or hits operating-imposed limits. This leads to application crashes, server restarts, or broader system instability that affects other services running on the same host. In cloud-native environments or containerized deployments, this can trigger automatic pod terminations due to out-of-memory conditions, causing service interruptions and potential data loss if state is not persisted externally. The severity of this impact is amplified in high-throughput scenarios where image processing occurs frequently, allowing an attacker to degrade system performance rapidly with minimal effort.
This vulnerability maps directly to the MITRE ATT&CK technique T1496, Resource Hijacking, specifically under the sub-technique for denial of service via resource exhaustion. It also relates to CWE-787, out-of-bounds write, in a broader sense if the leak leads to heap corruption during subsequent allocations, although the primary classification remains memory management failure. Security practitioners should note that this is not an arbitrary code execution vulnerability but rather a reliability and availability issue stemming from improper resource lifecycle management within the image processing pipeline.
Mitigation strategies must focus on immediate patching and architectural safeguards. The most effective remediation is to upgrade ImageMagick to version 6.9.13-58 or later for the legacy branch, or version 7.1.2-33 and above for the current major release series, where these memory leaks have been addressed by developers through rigorous code review and testing of the MSL decoder logic. For organizations unable to patch immediately due to dependency constraints, implementing strict resource limits is essential. This includes configuring operating system-level controls such as cgroups in Linux environments or container runtime limits to cap the maximum memory usage of ImageMagick processes. Additionally, web application firewalls can be tuned to detect and block requests containing MSL content if image processing services are not intended for public-facing XML-based inputs. Input validation should also enforce strict schemas that reject any non-image file types attempting to invoke the MSL decoder path, thereby reducing the attack surface available to potential adversaries seeking to exhaust system resources.