CVE-2025-53101: ImageMagick Buffer Overflow Vulnerability

CVE-2025-53101 Overview

CVE-2025-53101 is a stack overflow vulnerability in ImageMagick, the widely-used open-source software for editing and manipulating digital images. The vulnerability exists in ImageMagick's magick mogrify command, where specifying multiple consecutive %d format specifiers in a filename template causes internal pointer arithmetic to generate an address below the beginning of the stack buffer, resulting in a stack overflow through vsnprintf().

Critical Impact

This vulnerability allows remote attackers to potentially achieve arbitrary code execution or cause denial of service through crafted filename templates processed by ImageMagick's mogrify command.

Affected Products

• ImageMagick versions prior to 7.1.2-0
• ImageMagick versions prior to 6.9.13-26
• Systems using magick mogrify command with user-controlled filename templates

Discovery Timeline

• 2025-07-14 - CVE-2025-53101 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-53101

Vulnerability Analysis

This vulnerability stems from improper handling of format specifiers in filename templates within ImageMagick's mogrify command. When a user supplies a filename template containing multiple consecutive %d format specifiers, the internal pointer arithmetic miscalculates memory addresses. This miscalculation results in the generation of an address that falls below the legitimate beginning of the allocated stack buffer.

The vulnerable code path involves the vsnprintf() function, which writes formatted output to a buffer. Due to the erroneous pointer calculation, the function writes data outside the intended memory region, triggering a stack overflow condition. This memory corruption can be exploited to overwrite critical stack data such as return addresses, potentially enabling arbitrary code execution.

Root Cause

The root cause is classified as CWE-124 (Buffer Underwrite), where pointer arithmetic operations incorrectly calculate memory addresses when processing multiple %d format specifiers. The code fails to properly validate or limit the number of consecutive format specifiers, allowing the computed buffer pointer to reference memory locations before the start of the allocated stack buffer.

Attack Vector

The vulnerability is exploitable over the network without authentication or user interaction. An attacker can craft a malicious filename template containing multiple %d format specifiers and pass it to the magick mogrify command. This could occur through:

• Web applications that use ImageMagick to process user-uploaded images with filename templates
• Automated image processing pipelines that accept external input
• Command-line usage where filename parameters are derived from untrusted sources

The exploitation occurs when the vulnerable format specifier processing causes vsnprintf() to write beyond the stack buffer boundaries, corrupting adjacent memory and potentially hijacking program control flow.

Detection Methods for CVE-2025-53101

Indicators of Compromise

• Unexpected crashes or segmentation faults in ImageMagick processes, particularly in mogrify operations
• Core dumps indicating stack corruption in ImageMagick-related processes
• Abnormal memory access patterns in process monitoring showing addresses below expected stack regions
• Error logs containing vsnprintf or format string related errors from ImageMagick

Detection Strategies

• Monitor for ImageMagick process crashes with stack-related error signatures
• Implement input validation to detect filename templates with multiple consecutive %d specifiers
• Use application-level logging to track format specifier patterns in mogrify command inputs
• Deploy memory protection mechanisms (ASLR, stack canaries) that can detect exploitation attempts

Monitoring Recommendations

• Enable verbose logging for ImageMagick operations in production environments
• Configure system monitoring to alert on repeated ImageMagick process failures
• Implement file integrity monitoring on systems running ImageMagick to detect post-exploitation modifications
• Review web application logs for unusual filename patterns submitted to image processing endpoints

How to Mitigate CVE-2025-53101

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-0 or later for the 7.x branch
• Upgrade ImageMagick to version 6.9.13-26 or later for the 6.x branch
• Implement input sanitization to reject filename templates with multiple consecutive %d specifiers
• Consider restricting ImageMagick processing to controlled inputs until patching is complete

Patch Information

ImageMagick has released fixed versions that address this vulnerability. The patch is available through GitHub Commit 66dc8f5. For additional details, see the GitHub Security Advisory GHSA-qh3h-j545-h8c9. Debian users should also reference the Debian LTS Security Announcement for distribution-specific updates.

Fixed versions:

• ImageMagick 7.x: Version 7.1.2-0 and later
• ImageMagick 6.x: Version 6.9.13-26 and later

Workarounds

• Sanitize all filename template inputs to remove or escape format specifiers before passing to mogrify
• Implement strict input validation to reject filename templates containing multiple %d patterns
• Run ImageMagick processes in sandboxed environments with restricted permissions
• Use ImageMagick's policy.xml to restrict potentially dangerous operations until patching is possible

# Example: Check current ImageMagick version
magick --version

# Example: Update ImageMagick via package manager (Debian/Ubuntu)
sudo apt update && sudo apt install imagemagick

# Example: Verify patch application by checking version
magick --version | grep -E "7\.1\.[2-9]|6\.9\.13-(2[6-9]|[3-9][0-9])"