CVE-2026-53467 Overview
CVE-2026-53467 is a heap information disclosure vulnerability in ImageMagick, the free and open-source software used for editing and manipulating digital images. The flaw resides in the Multiple-image Network Graphics (MNG) decoder, where portions of decoded pixels are left unchanged. As a result, uninitialized heap memory can be returned within the pixel buffer, exposing potentially sensitive process memory to attackers who supply crafted MNG images. The issue is tracked under [CWE-200] Exposure of Sensitive Information to an Unauthorized Actor. It has been fixed in ImageMagick versions 6.9.13-51 and 7.1.2-26.
Critical Impact
Attackers can leak fragments of process heap memory by processing a crafted MNG file, which may reveal sensitive data from co-located allocations.
Affected Products
- ImageMagick 6.x prior to 6.9.13-51
- ImageMagick 7.x prior to 7.1.2-26
- Applications and services that embed ImageMagick for MNG decoding
Discovery Timeline
- 2026-07-01 - CVE-2026-53467 published to NVD
- 2026-07-01 - Last updated in NVD database
Technical Details for CVE-2026-53467
Vulnerability Analysis
The vulnerability affects the MNG decoder in ImageMagick. During decoding, the routine allocates a pixel buffer intended to hold the fully reconstructed image. The decoder does not overwrite every pixel in that buffer before returning it to the caller. Any bytes that remain untouched retain whatever heap contents existed at allocation time.
When the resulting image is written back out, converted, or served to a client, those stale bytes are transmitted with it. This exposes fragments of unrelated heap memory to an attacker who can supply the input file and observe the output.
The network attack vector applies to ImageMagick deployments that accept user-supplied images, including web upload endpoints, thumbnailing services, and document conversion pipelines. No authentication or user interaction is required for exploitation, but confidentiality is the only affected security property. Integrity and availability are not impacted.
Root Cause
The root cause is incomplete initialization of the output pixel buffer within the MNG decoder. The decoder assumes all pixels will be written during the frame reconstruction process, but certain code paths leave regions of the buffer unchanged. Because the buffer is drawn from the heap rather than zero-initialized memory, prior allocations remain readable through the returned image.
Attack Vector
An attacker crafts an MNG file that triggers the code path leaving pixels unmodified. The file is submitted to any application that uses ImageMagick to decode MNG input. The resulting image, containing residual heap bytes, is then retrieved by the attacker. Repeated submissions can be used to sample heap contents over time. See the GitHub Security Advisory GHSA-8g53-9m3c-69xg for the vendor's technical description.
Detection Methods for CVE-2026-53467
Indicators of Compromise
- Uploads of .mng files to image-processing endpoints that do not typically receive MNG input.
- Output images from ImageMagick pipelines containing visually anomalous pixel regions or noise bands consistent with uninitialized memory.
- Repeated requests from the same client submitting slightly varied MNG files to the same conversion endpoint.
Detection Strategies
- Inventory hosts running ImageMagick and compare installed versions against 6.9.13-51 and 7.1.2-26.
- Inspect web application logs for MNG uploads and correlate with the ImageMagick process invocations that handled them.
- Enable ImageMagick policy logging to record decoders invoked during conversion jobs.
Monitoring Recommendations
- Alert on invocations of the MNG decoder in environments where MNG is not an expected input format.
- Monitor image-processing worker processes for unusual output sizes or entropy that could indicate leaked heap content.
- Track package versions of ImageMagick, libmagickcore, and language bindings such as Wand and RMagick across the fleet.
How to Mitigate CVE-2026-53467
Immediate Actions Required
- Upgrade ImageMagick to 6.9.13-51 or 7.1.2-26 or later on all systems.
- Rebuild and redeploy container images and application bundles that statically include vulnerable ImageMagick libraries.
- Restrict accepted image formats at the application layer to only those required by the workload.
Patch Information
The maintainers fixed the issue in ImageMagick 6.9.13-51 and 7.1.2-26. Details are published in the GitHub Security Advisory GHSA-8g53-9m3c-69xg. Distributions typically ship backported fixes; verify that the installed package incorporates the referenced advisory.
Workarounds
- Disable the MNG coder in ImageMagick's policy.xml if MNG input is not required for the workload.
- Route image processing through a sandboxed worker with minimal heap contents to reduce the value of any leaked memory.
- Reject MNG uploads at the ingress layer using content-type and magic-byte inspection until patching is complete.
# Configuration example: disable the MNG coder in ImageMagick policy.xml
# Add the following inside the <policymap> element:
# <policy domain="coder" rights="none" pattern="MNG" />
sudo sed -i 's|</policymap>| <policy domain="coder" rights="none" pattern="MNG" />\n</policymap>|' /etc/ImageMagick-7/policy.xml
identify -list policy | grep -i mng
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
