CVE-2026-25968: ImageMagick Buffer Overflow Vulnerability

CVE-2026-25968 Overview

A critical stack buffer overflow vulnerability has been identified in ImageMagick, the widely-used open-source image processing software. The vulnerability exists in the MSL (Magick Scripting Language) processing component, specifically in the msl.c file. When processing certain attributes, a long value can overflow a fixed-size stack buffer, leading to memory corruption and potentially enabling remote code execution.

Critical Impact

This stack buffer overflow vulnerability allows unauthenticated remote attackers to potentially achieve code execution by supplying a maliciously crafted MSL file or image with embedded MSL content. The network-accessible nature with no user interaction required makes this a severe threat to systems processing untrusted images.

Affected Products

• ImageMagick versions prior to 7.1.2-15
• ImageMagick versions prior to 6.9.13-40
• Any application or service using vulnerable ImageMagick libraries for image processing

Discovery Timeline

• 2026-02-24 - CVE-2026-25968 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-25968

Vulnerability Analysis

This vulnerability is classified under CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). The flaw occurs during the processing of MSL attributes within ImageMagick's scripting language parser. When an attribute value exceeds the expected length, the parser fails to properly validate the input size before copying it into a fixed-size stack buffer, resulting in memory corruption.

The impact of successful exploitation is severe, as attackers can potentially overwrite return addresses or function pointers on the stack, redirecting program execution to attacker-controlled code. Since ImageMagick is commonly deployed in web applications, content management systems, and automated image processing pipelines, this vulnerability poses significant risk to internet-facing infrastructure.

Root Cause

The root cause lies in insufficient bounds checking in the msl.c source file when handling attribute values. The code allocates a fixed-size buffer on the stack to store attribute data but fails to verify that incoming attribute values do not exceed this buffer's capacity. This classic memory safety issue allows attackers to write beyond the allocated buffer boundaries.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by crafting a malicious MSL file or an image file containing embedded MSL content. When a vulnerable ImageMagick instance processes this file—whether through a web application upload, automated processing pipeline, or command-line invocation—the stack buffer overflow is triggered.

The attack can be delivered through multiple channels:

• Direct file uploads to web applications using ImageMagick for image processing
• Email attachments processed by mail servers with ImageMagick integration
• Content delivery systems that transform or resize images
• Any automated workflow that processes untrusted image content

Detection Methods for CVE-2026-25968

Indicators of Compromise

• Unexpected ImageMagick process crashes or segmentation faults during image processing
• Anomalous memory access patterns in ImageMagick processes detected by endpoint protection
• Unusual child processes spawned from ImageMagick binaries
• Presence of MSL files with abnormally long attribute values in upload directories

Detection Strategies

• Deploy file inspection rules to identify MSL content with oversized attribute values in uploaded files
• Monitor ImageMagick process behavior for signs of stack smashing or abnormal termination
• Implement application-level logging to capture detailed information about processed files and any parsing errors
• Use memory protection tools (ASLR, stack canaries) to detect exploitation attempts

Monitoring Recommendations

• Enable crash reporting and core dump analysis for ImageMagick processes to identify exploitation attempts
• Monitor system logs for repeated ImageMagick failures that may indicate active scanning or exploitation
• Implement file integrity monitoring on ImageMagick binaries and libraries
• Track network traffic patterns for suspicious file uploads to image processing endpoints

How to Mitigate CVE-2026-25968

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-15 or later (for 7.x series) or 6.9.13-40 or later (for 6.x series)
• If immediate patching is not possible, disable MSL processing in ImageMagick's policy configuration
• Review and restrict ImageMagick's policy.xml to limit dangerous operations
• Audit all applications and services that depend on ImageMagick for processing untrusted content

Patch Information

ImageMagick has released patched versions addressing this vulnerability. Users should update to version 7.1.2-15 for the 7.x branch or version 6.9.13-40 for the 6.x branch. The security advisory and patch details are available through the GitHub Security Advisory.

Workarounds

• Disable MSL coders by adding appropriate restrictions to ImageMagick's policy.xml configuration file
• Implement strict input validation to reject files containing MSL content before ImageMagick processing
• Use containerization or sandboxing to isolate ImageMagick processes from critical system resources
• Consider using alternative image processing libraries for handling untrusted content until patching is complete

# Configuration example - Restrict MSL processing in policy.xml
# Add the following to /etc/ImageMagick-7/policy.xml (adjust path for your installation)
<policy domain="coder" rights="none" pattern="MSL" />
<policy domain="coder" rights="none" pattern="MVG" />
<policy domain="coder" rights="none" pattern="URL" />
<policy domain="coder" rights="none" pattern="HTTPS" />
<policy domain="coder" rights="none" pattern="HTTP" />