CVE-2026-40169: ImageMagick heap overflow in YAML and JSON encoders

Quick answers

Is CVE-2026-40169 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40169 being exploited in the wild.

How severe is CVE-2026-40169?

Medium severity, with a CVSS score of 6.2, published 13 April 2026.

Which products and versions are affected?

Dlemstra Magick.NET < 14.12.0; Magick.NET-Q16-AnyCPU (NuGet) < 14.12.0, ECOSYSTEM:introduced=0,fixed=14.12.0; Magick.NET-Q16-arm64 (NuGet) < 14.12.0, ECOSYSTEM:introduced=0,fixed=14.12.0; Magick.NET-Q16-HDRI-AnyCPU (NuGet) < 14.12.0, ECOSYSTEM:introduced=0,fixed=14.12.0; and 14 more.

Is there a fix for CVE-2026-40169?

Yes. Magick.NET-Q16-AnyCPU (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-HDRI-AnyCPU (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-HDRI-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-HDRI-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-HDRI-x64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-HDRI-x86 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-OpenMP-x64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-x64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q16-x86 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-AnyCPU (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-OpenMP-x64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-x64 (NuGet): upgrade to 14.12.0 or later; Magick.NET-Q8-x86 (NuGet): upgrade to 14.12.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-40169 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-40169?

Check whether you run Dlemstra Magick.NET, ImageMagick, Magick.NET-Q16-AnyCPU (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

• Magick.NET-Q16-AnyCPU (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-AnyCPU --version 14.12.0

• Magick.NET-Q16-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-arm64 --version 14.12.0

• Magick.NET-Q16-HDRI-AnyCPU (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-HDRI-AnyCPU --version 14.12.0

• Magick.NET-Q16-HDRI-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-HDRI-arm64 --version 14.12.0

• Magick.NET-Q16-HDRI-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-HDRI-OpenMP-arm64 --version 14.12.0

• Magick.NET-Q16-HDRI-x64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-HDRI-x64 --version 14.12.0

• Magick.NET-Q16-HDRI-x86 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-HDRI-x86 --version 14.12.0

• Magick.NET-Q16-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-OpenMP-arm64 --version 14.12.0

• Magick.NET-Q16-OpenMP-x64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-OpenMP-x64 --version 14.12.0

• Magick.NET-Q16-x64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-x64 --version 14.12.0

• Magick.NET-Q16-x86 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q16-x86 --version 14.12.0

• Magick.NET-Q8-AnyCPU (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-AnyCPU --version 14.12.0

• Magick.NET-Q8-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-arm64 --version 14.12.0

• Magick.NET-Q8-OpenMP-arm64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-OpenMP-arm64 --version 14.12.0

• Magick.NET-Q8-OpenMP-x64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-OpenMP-x64 --version 14.12.0

• Magick.NET-Q8-x64 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-x64 --version 14.12.0

• Magick.NET-Q8-x86 (NuGet): upgrade to 14.12.0 or later

  dotnet add package Magick.NET-Q8-x86 --version 14.12.0

Technical details

A heap-based buffer overflow (CWE-122) exists in ImageMagick's YAML and JSON encoders. The vulnerability is triggered when the software attempts to write image data to YAML or JSON output formats. An attacker can provide a specially crafted image file that, when processed, results in an out-of-bounds write on the heap. This typically results in a process crash (Denial of Service). The issue is addressed in ImageMagick version 7.1.2-19 and Magick.NET version 14.12.0.

Affected products

• ImageMagick ImageMagick < 7.1.2-19
• dlemstra Magick.NET < 14.12.0

Identifiers

• CVE-2026-40169
• GHSA-5592-p365-24xh

Timeline

• 2026-04-13: advisory: NVD publication date
• 2026-04-14: disclosed: GitHub Advisory published

References

• https://api.github.com/users/zer0matt
• https://github.com/zer0matt
• https://api.github.com/users/zer0matt/gists%7B/gist_id%7D
• https://api.github.com/users/zer0matt/repos
• https://avatars.githubusercontent.com/u/28620328?v=4
• https://api.github.com/users/zer0matt/events%7B/privacy%7D