CVE-2026-25989: ImageMagick DoS Vulnerability via SVG File

CVE-2026-25989 Overview

CVE-2026-25989 is a denial of service vulnerability in ImageMagick, the widely-used open-source software for editing and manipulating digital images. The vulnerability stems from an off-by-one error in boundary checking when processing crafted SVG files. An incorrect boundary comparison using > instead of >= allows attackers to bypass security guards and trigger an undefined (size_t) cast, leading to application crashes and service disruption.

Critical Impact

Attackers can remotely crash ImageMagick instances by submitting maliciously crafted SVG files, potentially disrupting image processing services and web applications that rely on ImageMagick for image conversion.

Affected Products

• ImageMagick versions prior to 7.1.2-15
• ImageMagick versions prior to 6.9.13-40
• Applications and services utilizing vulnerable ImageMagick libraries for SVG processing

Discovery Timeline

• 2026-02-24 - CVE-2026-25989 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-25989

Vulnerability Analysis

This vulnerability is classified under CWE-193 (Off-by-One Error) and CWE-190 (Integer Overflow or Wraparound). The flaw exists in ImageMagick's SVG file parsing functionality where a boundary validation check incorrectly uses a greater-than operator (>) instead of the correct greater-than-or-equal operator (>=). This subtle programming mistake creates a boundary condition where an attacker can craft an SVG file that passes the security check but still reaches code paths that were meant to be protected.

When the malformed SVG file is processed, the bypassed guard leads to an undefined (size_t) cast operation. This undefined behavior can cause memory corruption, unexpected program states, or application crashes, resulting in a denial of service condition. The vulnerability is particularly concerning for web services and applications that automatically process user-uploaded images.

Root Cause

The root cause is an off-by-one boundary check error in the SVG parsing code. The incorrect comparison operator allows input values at the exact boundary to slip through validation, subsequently triggering undefined behavior during integer type casting. This is a classic example of a fence-post error where the developer failed to account for the inclusive boundary case.

Attack Vector

The attack is network-accessible and requires no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Crafting a malicious SVG file with specific dimensions or attributes designed to trigger the off-by-one condition
2. Submitting the SVG file to any application or service that processes images using vulnerable ImageMagick versions
3. The malformed input bypasses the boundary check and reaches the undefined cast operation
4. ImageMagick crashes or enters an undefined state, causing denial of service

The vulnerability is particularly dangerous for web applications that accept SVG uploads for conversion, thumbnail generation, or image processing pipelines. See the ImageMagick Security Advisory for technical details.

Detection Methods for CVE-2026-25989

Indicators of Compromise

• Unexpected ImageMagick process crashes or restarts when processing SVG files
• Abnormal memory usage patterns in ImageMagick-dependent services
• Error logs showing size_t cast failures or segmentation faults during SVG processing
• Increased submission of SVG files from suspicious sources

Detection Strategies

• Monitor ImageMagick process stability and crash frequency with automated alerting
• Implement file type validation and scanning for malformed SVG structures before processing
• Deploy application-level logging to capture SVG processing failures and anomalies
• Use SentinelOne Singularity to detect abnormal process behavior and crash patterns

Monitoring Recommendations

• Enable verbose logging for ImageMagick operations to capture detailed error information
• Set up alerts for repeated SVG processing failures from the same source
• Monitor system resources for memory exhaustion patterns associated with DoS attacks
• Track ImageMagick version deployments across your infrastructure for vulnerability management

How to Mitigate CVE-2026-25989

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
• Review all applications and containers using ImageMagick and schedule immediate patching
• Consider temporarily disabling SVG processing if immediate patching is not possible

Patch Information

ImageMagick has released patches in versions 7.1.2-15 and 6.9.13-40 that correct the boundary check operator from > to >=, properly preventing the off-by-one bypass. Organizations should prioritize upgrading to these patched versions. Detailed patch information is available in the ImageMagick Security Advisory.

Workarounds

• Disable SVG processing in ImageMagick by modifying the policy.xml configuration file
• Implement input validation to reject or sanitize SVG files before ImageMagick processing
• Use a Web Application Firewall (WAF) to filter potentially malicious SVG uploads
• Isolate ImageMagick processing in sandboxed environments to limit DoS impact

# Disable SVG processing in ImageMagick policy.xml
# Add the following to /etc/ImageMagick-7/policy.xml or equivalent
<policy domain="coder" rights="none" pattern="SVG" />