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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-13 · updated 2026-06-17
Weakness: CWE-122

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.

Affected products

ImageMagick: before 7.1.2-19 — fixed in 7.1.2-19

How to fix

Upgrade to a fixed version: ImageMagick 7.1.2-19. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2026-40183 or the next vulnerability affects your stack