CVE-2026-40183: ImageMagick heap buffer overflow in JXL encoder

CVE-2026-40183 · Severity: medium · CVSS 5.5 · Published 2026-04-14

ImageMagick, a widely used software suite for displaying and converting images, is vulnerable to a memory-related flaw when processing JPEG XL (JXL) images. If a user is tricked into processing a specially crafted image file using 16-bit float encoding, the application may crash or become unresponsive. This could lead to a denial of service, impacting automated image processing workflows or applications that rely on ImageMagick for content rendering.

Technologies: Magick.NET-Q16-AnyCPU (NuGet), Magick.NET-Q16-arm64 (NuGet), Magick.NET-Q16-HDRI-AnyCPU (NuGet), Magick.NET-Q16-HDRI-arm64 (NuGet), Magick.NET-Q16-HDRI-OpenMP-arm64 (NuGet), Magick.NET-Q16-HDRI-x64 (NuGet), Magick.NET-Q16-HDRI-x86 (NuGet), Magick.NET-Q16-OpenMP-arm64 (NuGet), Magick.NET-Q16-OpenMP-x64 (NuGet), Magick.NET-Q16-x64 (NuGet), Magick.NET-Q16-x86 (NuGet), Magick.NET-Q8-AnyCPU (NuGet), Magick.NET-Q8-arm64 (NuGet), Magick.NET-Q8-OpenMP-arm64 (NuGet), Magick.NET-Q8-OpenMP-x64 (NuGet), Magick.NET-Q8-x64 (NuGet), Magick.NET-Q8-x86 (NuGet). Vendors: NuGet.

Quick answers

Is CVE-2026-40183 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-40183 being exploited in the wild.
How severe is CVE-2026-40183?
Medium severity, with a CVSS score of 5.5, published 14 April 2026.
Which products and versions are affected?
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; Magick.NET-Q16-HDRI-arm64 (NuGet) < 14.12.0, ECOSYSTEM:introduced=0,fixed=14.12.0; and 13 more.
Is there a fix for CVE-2026-40183?
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-2026-40183 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-40183?
Check whether you run Magick.NET-Q16-AnyCPU (NuGet), Magick.NET-Q16-arm64 (NuGet), Magick.NET-Q16-HDRI-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 the JXL encoder of ImageMagick. The vulnerability is triggered when a user specifies that an image should be encoded as 16-bit floats, leading to an out-of-bounds write on the heap. The attack vector is local and requires user interaction, such as opening or processing a malicious image file. Successful exploitation primarily impacts system availability by causing a crash (Denial of Service). The issue has been 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-2026-40183
  • GHSA-jvgr-9ph5-m8v4

Timeline

  • 2026-04-13: disclosed
  • 2026-04-13: patched: Fixed in ImageMagick 7.1.2-19 and Magick.NET 14.12.0
  • 2026-04-14: advisory

References

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