CVE-2026-25987: ImageMagick Buffer Overflow Vulnerability

CVE-2026-25987 Overview

A heap buffer over-read vulnerability has been identified in ImageMagick, the widely-used open-source software for editing and manipulating digital images. This vulnerability exists in the MAP image decoder when processing crafted MAP files, potentially leading to crashes or unintended memory disclosure during image decoding.

Critical Impact

This vulnerability can be exploited remotely without authentication, potentially allowing attackers to crash affected systems or extract sensitive memory contents through maliciously crafted MAP image files.

Affected Products

• ImageMagick versions prior to 7.1.2-15
• ImageMagick versions prior to 6.9.13-40

Discovery Timeline

• 2026-02-24 - CVE-2026-25987 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-25987

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), which occurs when the software reads data past the end, or before the beginning, of the intended buffer. In the context of ImageMagick's MAP image decoder, the vulnerability manifests when processing specially crafted MAP files.

The MAP image format is used by ImageMagick to store indexed color images with a separate colormap. When the decoder processes a malformed MAP file, insufficient bounds checking allows the application to read beyond the allocated heap buffer. This can result in two primary impacts: application crashes due to accessing invalid memory regions, and potential information disclosure if the out-of-bounds memory contains sensitive data that gets exposed through the decoded image output or error messages.

Root Cause

The root cause of this vulnerability lies in improper boundary validation within the MAP image decoder component. When processing MAP file headers or colormap data, the decoder fails to adequately verify that the requested read operations stay within the bounds of the allocated buffer. This allows an attacker to craft a MAP file with manipulated header values that cause the decoder to read beyond the intended memory region.

Attack Vector

This vulnerability can be exploited remotely over the network without requiring authentication or user interaction. An attacker can deliver a malicious MAP file through various vectors including:

• Web applications that process user-uploaded images using ImageMagick
• Email attachments processed by automated systems
• Content management systems with image processing capabilities
• Any service that accepts and processes images from untrusted sources

The exploitation technique involves crafting a MAP file with specially manipulated header values that specify dimensions or colormap entries exceeding the actual data present in the file. When ImageMagick attempts to decode this file, it reads past the end of the allocated heap buffer. For technical details on the vulnerability mechanism, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-25987

Indicators of Compromise

• Unexpected crashes in ImageMagick processes, particularly when processing MAP format images
• Abnormal memory access patterns or segmentation faults in image processing workflows
• Error logs indicating memory read violations in image decoder components
• Unusual MAP files appearing in upload directories or processing queues

Detection Strategies

• Monitor ImageMagick process behavior for unexpected terminations or crash dumps
• Implement file type validation to identify and quarantine suspicious MAP files before processing
• Deploy memory protection tools such as AddressSanitizer (ASan) in development environments to detect out-of-bounds read attempts
• Review application logs for ImageMagick decoder errors related to MAP file processing

Monitoring Recommendations

• Configure centralized logging for all ImageMagick processing operations
• Set up alerts for repeated ImageMagick process crashes or restarts
• Monitor network traffic for unusual patterns of MAP file uploads to exposed services
• Implement file integrity monitoring on image processing directories

How to Mitigate CVE-2026-25987

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-15 or later for the 7.x branch
• Upgrade ImageMagick to version 6.9.13-40 or later for the 6.x branch
• Audit all systems running ImageMagick to identify vulnerable installations
• Review and restrict network-accessible services that process images

Patch Information

The ImageMagick development team has released patches in versions 7.1.2-15 and 6.9.13-40 that address this heap buffer over-read vulnerability. Organizations should prioritize updating to these patched versions immediately. For detailed information about the security fix, see the GitHub Security Advisory.

Workarounds

• Disable MAP image format support in ImageMagick by configuring the policy.xml file to deny MAP format processing
• Implement input validation to reject MAP files from untrusted sources before they reach ImageMagick
• Deploy ImageMagick in an isolated sandboxed environment to limit the impact of potential exploitation
• Use network segmentation to restrict access to image processing services

# Configuration example - Disable MAP format in ImageMagick policy.xml
# Add the following to /etc/ImageMagick-7/policy.xml or equivalent location
<policy domain="coder" rights="none" pattern="MAP" />