5.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-40183

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

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.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2026-40183

CVE-2026-40183:

5.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
Magick.NET-Q16-AnyCPU	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-HDRI-AnyCPU	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-HDRI-OpenMP-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-HDRI-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-HDRI-x64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-HDRI-x86	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-OpenMP-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-OpenMP-x64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-x64	nuget	< 14.12.0	14.12.0
Magick.NET-Q16-x86	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-AnyCPU	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-OpenMP-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-OpenMP-x64	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-arm64	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-x64	nuget	< 14.12.0	14.12.0
Magick.NET-Q8-x86	nuget	< 14.12.0	14.12.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The analysis of the provided commit 1c7767fc5f822c6edc104c1220d523e96fa20b5a clearly indicates that the vulnerability is located in the WriteJXLImage function within the coders/jxl.c file. The patch modifies the logic for calculating the buffer size needed to store JXL image data. Specifically, the original code failed to account for the size of 16-bit float samples (JXL_TYPE_FLOAT16), resulting in an allocation that was too small. The subsequent attempt to write the full image data into this buffer would cause a heap-based buffer overflow. The fix involves adding a check for JXL_TYPE_FLOAT16 and using the correct sample size (sizeof(float)) in the buffer size calculation. Therefore, any runtime profile during the exploitation of this vulnerability would show the WriteJXLImage function in the stack trace.

Vulnerable functions

WriteJXLImage

coders/jxl.c

The vulnerability lies in the `WriteJXLImage` function where the size of the buffer (`channels_size`) for holding image pixel data was incorrectly calculated for 16-bit float JXL images. The original code did not properly handle the `JXL_TYPE_FLOAT16` data type, causing it to default to a smaller size (`sizeof(char)`) instead of the correct size (`sizeof(float)`). This led to a heap buffer overflow when the image data was written to the undersized buffer. The patch corrects this by introducing `sample_size` and explicitly checking for `JXL_TYPE_FLOAT16` to ensure the correct buffer size is allocated.

Vulnerability Intelligence
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WAF Protection Rules

WAF Rule

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Reasoning

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