CVE-2026-25967: ImageMagick Buffer Overflow Vulnerability

CVE-2026-25967 Overview

CVE-2026-25967 is a stack-based buffer overflow vulnerability in ImageMagick, a widely-used free and open-source software suite for editing and manipulating digital images. This vulnerability exists in the FTXT image reader component and can be exploited when ImageMagick processes a specially crafted FTXT file. The flaw causes out-of-bounds writes on the stack, which leads to application crashes and denial of service conditions.

Critical Impact

Processing malicious FTXT image files can trigger out-of-bounds stack writes, causing application crashes and potential denial of service for systems relying on ImageMagick for image processing operations.

Affected Products

• ImageMagick versions prior to 7.1.2-15
• Applications and services utilizing vulnerable ImageMagick libraries for image processing
• Web applications that accept user-uploaded images processed through ImageMagick

Discovery Timeline

• 2026-02-24 - CVE-2026-25967 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-25967

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). The flaw resides in the FTXT image reader component within ImageMagick, which fails to properly validate input boundaries when parsing FTXT format files.

When ImageMagick attempts to process a maliciously crafted FTXT file, the parser does not adequately check the size of data being written to stack-allocated buffers. This oversight allows an attacker to supply input that exceeds the expected buffer size, resulting in data being written beyond the allocated memory region on the stack.

The vulnerability can be triggered remotely via network-accessible services that process user-supplied images using ImageMagick. No authentication or user interaction is required to exploit this vulnerability, making it particularly concerning for web applications and image processing pipelines that handle untrusted input.

Root Cause

The root cause of this vulnerability is insufficient bounds checking in the FTXT image format parsing code. The FTXT reader allocates a fixed-size buffer on the stack and copies input data without verifying that the data length does not exceed the buffer capacity. This classic buffer overflow pattern allows carefully constructed input to overflow the buffer and corrupt adjacent stack memory.

Attack Vector

The attack vector is network-based, requiring an attacker to deliver a malicious FTXT file to a system running vulnerable ImageMagick versions. Common attack scenarios include:

• Uploading malicious FTXT files to web applications that process images using ImageMagick
• Sending crafted files through email attachments that are automatically processed
• Exploiting image conversion services or APIs that accept FTXT format input

The vulnerability triggers when the malicious file is parsed, causing stack corruption that results in application termination. The attack does not require authentication or special privileges, and no user interaction is needed beyond the target system processing the malicious file.

The vulnerability mechanism involves improper handling of FTXT file parsing where oversized input data is written to a stack buffer without proper boundary validation. For detailed technical analysis of the vulnerability, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-25967

Indicators of Compromise

• Unexpected ImageMagick process crashes or termination events in system logs
• Presence of suspicious FTXT files in upload directories or image processing queues
• Application logs showing segmentation faults or stack smashing detection during image processing
• Unusual network activity targeting image upload endpoints with FTXT content

Detection Strategies

• Monitor ImageMagick processes for abnormal termination signals (SIGSEGV, SIGABRT)
• Implement file type validation to identify and quarantine suspicious FTXT files before processing
• Deploy application-level logging to track all image processing operations and their outcomes
• Use runtime application self-protection (RASP) solutions to detect stack overflow attempts

Monitoring Recommendations

• Enable core dump collection for ImageMagick processes to facilitate forensic analysis of crashes
• Configure centralized logging for all image processing components across the environment
• Implement alerting for repeated processing failures that may indicate exploitation attempts
• Monitor system resource utilization for signs of denial of service attacks targeting image processing

How to Mitigate CVE-2026-25967

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-15 or later immediately
• Audit all systems and applications for ImageMagick installations and verify version numbers
• Implement input validation to reject or quarantine FTXT format files until systems are patched
• Review application logs for evidence of exploitation attempts prior to patching

Patch Information

ImageMagick version 7.1.2-15 contains the security patch that addresses this vulnerability. Organizations should update to this version or later to remediate the stack-based buffer overflow in the FTXT image reader. The patch information and additional details are available in the GitHub Security Advisory.

Workarounds

• Disable FTXT format support in ImageMagick's policy.xml configuration file if not required
• Implement a file type allowlist that excludes FTXT format from processing pipelines
• Deploy network-level filtering to block FTXT files at the perimeter
• Run ImageMagick processes in sandboxed environments with limited system access

# Configuration example: Disable FTXT format in ImageMagick policy.xml
# Add the following to /etc/ImageMagick-7/policy.xml
<policy domain="coder" rights="none" pattern="FTXT" />

# Verify the policy is applied
identify -list policy | grep FTXT