CVE-2026-25897: ImageMagick Buffer Overflow Vulnerability

CVE-2026-25897 Overview

CVE-2026-25897 is a critical Integer Overflow vulnerability affecting ImageMagick, the widely-used open-source software for editing and manipulating digital images. The flaw exists in the sun decoder component and affects 32-bit systems and builds. When processing a specially crafted image file, an integer overflow condition can occur that leads to an out-of-bounds heap write, potentially enabling attackers to execute arbitrary code or cause denial of service.

Critical Impact

This vulnerability allows remote attackers to potentially achieve code execution on vulnerable 32-bit ImageMagick deployments by sending a malicious image file, requiring no authentication or user interaction beyond processing the image.

Affected Products

• ImageMagick versions prior to 7.1.2-15
• ImageMagick versions prior to 6.9.13-40
• 32-bit systems and builds running vulnerable ImageMagick versions

Discovery Timeline

• 2026-02-24 - CVE-2026-25897 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-25897

Vulnerability Analysis

This vulnerability combines two weaknesses: Integer Overflow (CWE-190) and Heap-based Buffer Overflow (CWE-122). The flaw resides in ImageMagick's sun decoder, which is responsible for parsing Sun Rasterfile image formats. On 32-bit architectures, insufficient validation of image dimension parameters allows an attacker to trigger an integer overflow during memory allocation calculations.

When the sun decoder processes specially crafted image dimensions, the multiplication of width, height, and pixel depth values can overflow the 32-bit integer boundary. This results in a smaller-than-expected memory buffer being allocated. Subsequent write operations then exceed the allocated buffer boundaries, causing heap memory corruption.

The network attack vector makes this particularly dangerous in web applications and automated image processing pipelines where ImageMagick processes untrusted image uploads. No authentication or privileges are required to exploit this vulnerability.

Root Cause

The root cause is inadequate integer overflow checking in the sun decoder's dimension parsing logic. When calculating the required buffer size for image data, the code multiplies user-controlled image dimensions without proper bounds validation. On 32-bit systems, these calculations can wrap around, resulting in a truncated allocation size while the actual data written remains based on the original dimensions.

Attack Vector

The attack vector is network-based, requiring an attacker to deliver a malicious Sun Rasterfile image to a vulnerable ImageMagick installation. Common exploitation scenarios include:

• Web applications that process user-uploaded images using ImageMagick
• Email systems that generate image thumbnails
• Content management systems with automatic image processing
• Any service accepting and converting image files on 32-bit infrastructure

The attacker crafts an image with specific dimension values designed to cause integer overflow when multiplied together on 32-bit systems. When ImageMagick attempts to decode this image, the undersized buffer allocation followed by oversized writes corrupts heap memory, potentially allowing code execution or system crash.

Detection Methods for CVE-2026-25897

Indicators of Compromise

• Unexpected crashes or segmentation faults in ImageMagick processes when handling image files
• Abnormal memory consumption patterns during image processing operations
• Core dumps showing heap corruption signatures in ImageMagick binaries
• Log entries indicating failed image conversions with Sun Rasterfile formats

Detection Strategies

• Monitor ImageMagick process stability and crash frequency for anomalies
• Implement file type validation to detect and log Sun Rasterfile submissions
• Deploy memory corruption detection tools (e.g., AddressSanitizer) in testing environments
• Use application-level monitoring to track image processing failures and exceptions

Monitoring Recommendations

• Enable verbose logging for image processing pipelines to capture format-specific errors
• Configure system monitoring to alert on ImageMagick process crashes or unexpected terminations
• Implement file upload analysis to identify potentially malicious image files before processing
• Monitor for unusual Sun Rasterfile image submissions, particularly with abnormal dimensions

How to Mitigate CVE-2026-25897

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-15 or later (for 7.x branch)
• Upgrade ImageMagick to version 6.9.13-40 or later (for 6.x branch)
• Audit systems to identify any 32-bit ImageMagick deployments
• Review image processing pipelines for exposure to untrusted image uploads

Patch Information

ImageMagick has released patched versions that address this integer overflow vulnerability. The fix is included in versions 7.1.2-15 and 6.9.13-40. Organizations should update to these versions or later immediately. For detailed patch information and security guidance, refer to the ImageMagick Security Advisory.

Workarounds

• Disable sun decoder support via ImageMagick policy configuration if Sun Rasterfile processing is not required
• Consider migrating 32-bit deployments to 64-bit systems where the overflow is not exploitable
• Implement strict file type validation to reject Sun Rasterfile formats at the application layer
• Use a web application firewall to filter image uploads before they reach ImageMagick

# ImageMagick policy.xml configuration to disable sun decoder
# Add to /etc/ImageMagick-7/policy.xml or equivalent location
# Disabling the sun coder prevents exploitation via this attack vector

# Add inside the <policymap> element:
# <policy domain="coder" rights="none" pattern="SUN" />