CVE-2025-43965: ImageMagick Buffer Overflow Vulnerability

CVE-2025-43965 Overview

CVE-2025-43965 is an Incorrect Calculation of Buffer Size vulnerability (CWE-131) affecting ImageMagick's MIFF (Magick Image File Format) image processing functionality. The vulnerability occurs when image depth is mishandled after the SetQuantumFormat function is used, potentially allowing attackers to compromise image data integrity through maliciously crafted MIFF files.

ImageMagick is a widely deployed open-source image processing library used by countless web applications, content management systems, and automated image processing pipelines. This vulnerability's network attack vector and lack of required authentication make it particularly concerning for environments that process untrusted image uploads.

Critical Impact

Remote attackers can exploit this vulnerability to compromise image data integrity without authentication. Systems processing untrusted MIFF images are at risk.

Affected Products

• ImageMagick versions prior to 7.1.1-44
• Debian Linux 11.0

Discovery Timeline

• 2025-04-23 - CVE-2025-43965 published to NVD
• 2025-12-31 - Last updated in NVD database

Technical Details for CVE-2025-43965

Vulnerability Analysis

The vulnerability resides in ImageMagick's MIFF image format processing code. MIFF is ImageMagick's native image format that supports various image properties including depth, colorspace, and compression. When processing MIFF images, the SetQuantumFormat function is used to configure quantum depth settings for pixel data handling.

The core issue involves incorrect calculation of buffer sizes (CWE-131) when the image depth parameter is processed after SetQuantumFormat has been invoked. This mishandling can lead to incorrect memory allocations or improper data interpretation, resulting in integrity violations of the processed image data.

The vulnerability is exploitable remotely without requiring user interaction or authentication. An attacker can craft a malicious MIFF image file that, when processed by a vulnerable ImageMagick installation, triggers the depth mishandling condition.

Root Cause

The root cause is an incorrect buffer size calculation when handling image depth values after the SetQuantumFormat function modifies the quantum format state. The depth parameter is not properly synchronized with the quantum format settings, leading to improper processing of pixel data and potential integrity issues.

Attack Vector

The vulnerability can be exploited through network-based attack vectors where an attacker supplies a specially crafted MIFF image file to an application using a vulnerable version of ImageMagick. Common attack scenarios include:

Exploitation requires delivering a malicious MIFF file to a target system running ImageMagick. This can occur through web application file upload features, email processing systems, document conversion services, or any automated image processing pipeline. The attacker crafts a MIFF image with specific depth parameters designed to trigger the mishandling condition when SetQuantumFormat is invoked during processing. See the ImageMagick security commit for technical details on the vulnerable code path.

Detection Methods for CVE-2025-43965

Indicators of Compromise

• Unusual MIFF image files with abnormal depth values being processed by ImageMagick
• Unexpected image corruption or processing errors in ImageMagick logs
• Anomalous file uploads containing MIFF format images from untrusted sources

Detection Strategies

• Monitor ImageMagick processing logs for MIFF format parsing errors or depth-related warnings
• Implement file type validation to identify and flag MIFF images from untrusted sources
• Deploy integrity monitoring on systems running ImageMagick to detect unexpected behavioral changes
• Use SentinelOne Singularity platform to monitor process behavior of ImageMagick instances

Monitoring Recommendations

• Enable verbose logging in ImageMagick to capture detailed processing information
• Monitor for unusual patterns in image processing workloads or unexpected MIFF file processing
• Track ImageMagick process memory usage patterns that may indicate exploitation attempts

How to Mitigate CVE-2025-43965

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.1-44 or later immediately
• Review and restrict MIFF format processing if not required by your application
• Implement input validation and sanitization for all image uploads
• Consider using ImageMagick policy files to disable MIFF format processing until patching is complete

Patch Information

The ImageMagick development team has addressed this vulnerability in version 7.1.1-44, released on February 22, 2025. The fix is available in the official ImageMagick commit. Debian users should refer to the Debian LTS security announcement for distribution-specific patching guidance.

Workarounds

• Disable MIFF format processing using ImageMagick policy configuration
• Implement strict file type filtering to block MIFF images from untrusted sources
• Use application-level sandboxing or containerization to isolate ImageMagick processing

# ImageMagick policy.xml configuration to disable MIFF format processing
# Add the following to /etc/ImageMagick-7/policy.xml within the <policymap> section:
<policy domain="coder" rights="none" pattern="MIFF" />