CVE-2026-55577: ImageMagick Buffer Overflow Vulnerability

CVE-2026-55577 Overview

CVE-2026-55577 is a heap buffer overflow vulnerability in ImageMagick, the open-source image editing and manipulation library. The flaw resides in the Magick Vector Graphics (MVG) decoder and can trigger an out-of-bounds write when the library processes a crafted image. The issue affects versions prior to 6.9.13-51 and 7.1.2-26. ImageMagick's maintainers addressed the flaw in those release versions. The weakness is categorized under [CWE-754] (Improper Check for Unusual or Exceptional Conditions).

Critical Impact
Successful exploitation causes heap memory corruption in the MVG decoder, leading to application crashes and potential denial of service in services that automatically process untrusted images.

Affected Products

ImageMagick versions prior to 6.9.13-51
ImageMagick versions prior to 7.1.2-26
Applications and services embedding vulnerable ImageMagick builds for image processing

Discovery Timeline

2026-07-01 - CVE-2026-55577 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-55577

Vulnerability Analysis

The vulnerability exists in ImageMagick's MVG (Magick Vector Graphics) decoder. When the decoder parses a crafted MVG input, it performs a heap write outside the bounds of an allocated buffer. This out-of-bounds write corrupts adjacent heap memory structures.

MVG is a text-based vector format that ImageMagick interprets to render primitives such as paths, strokes, and fills. Parsing malformed MVG content causes the decoder to miscalculate buffer boundaries. The result is a heap buffer overflow reachable through any interface that accepts MVG data or image inputs that trigger MVG parsing paths.

Availability impact is high per the CVSS vector, while confidentiality and integrity are rated none. This profile aligns with a crash-oriented memory corruption issue rather than data disclosure or code execution.

Root Cause

The root cause is improper handling of an exceptional condition during MVG decoding [CWE-754]. The decoder fails to validate a boundary state before writing to a heap-allocated buffer, allowing a crafted input to force the write past the allocation.

Attack Vector

An attacker delivers a crafted image or MVG payload to a target that invokes ImageMagick for processing. Common exposure points include upload endpoints, thumbnail generators, image conversion pipelines, and content management systems that use ImageMagick as a backend. No authentication or user interaction is required, but attack complexity is high, reflecting the conditions needed to reliably trigger the overflow. See the GitHub Security Advisory for maintainer-provided technical detail.

Detection Methods for CVE-2026-55577

Indicators of Compromise

Unexpected crashes or segmentation faults in convert, magick, or identify processes handling user-supplied images
Core dumps referencing MVG parsing functions within ImageMagick libraries
Abnormal restarts of web workers or image processing services following image upload events

Detection Strategies

Inventory hosts running ImageMagick and compare installed versions against 6.9.13-51 and 7.1.2-26
Inspect uploaded images and MVG files for anomalous drawing primitives or oversized structural fields
Correlate image processing service crashes with recent inbound uploads to identify probing attempts

Monitoring Recommendations

Enable crash reporting and core dump collection on hosts running ImageMagick
Log all image processing operations with source IP, file hash, and MIME type for post-incident review
Alert on repeated worker restarts or elevated error rates from image conversion services

How to Mitigate CVE-2026-55577

Immediate Actions Required

Upgrade ImageMagick to version 6.9.13-51 or 7.1.2-26 or later on all affected systems
Audit application dependencies and container images that bundle ImageMagick and rebuild with patched versions
Restrict image processing services to non-privileged accounts to limit the blast radius of a crash

Patch Information

ImageMagick maintainers fixed the heap buffer overflow in versions 6.9.13-51 and 7.1.2-26. Refer to the GitHub Security Advisory GHSA-wx47-rm3x-jx6p for release notes and commit references.

Workarounds

Disable the MVG coder in ImageMagick's policy.xml if MVG processing is not required
Validate and restrict accepted image formats at the application layer before passing files to ImageMagick
Run ImageMagick within a sandbox or container with strict resource limits to contain crashes

bash

# Configuration example: disable the MVG coder in ImageMagick policy.xml
# Add the following inside the <policymap> element
<policy domain="coder" rights="none" pattern="MVG" />
<policy domain="coder" rights="none" pattern="MSL" />