GreycLab CImg prior .3.7.5 BMP File nb_colors memory allocation

Summaryinfo

A vulnerability categorized as problematic has been discovered in GreycLab CImg. This vulnerability affects unknown code of the component BMP File Handler. Executing a manipulation of the argument nb_colors can lead to memory allocation. This vulnerability is tracked as CVE-2026-42146. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in GreycLab CImg and classified as problematic. This vulnerability affects an unknown functionality of the component BMP File Handler. The manipulation of the argument nb_colors with an unknown input leads to a memory allocation vulnerability. The CWE definition for the vulnerability is CWE-789. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. As an impact it is known to affect availability. CVE summarizes:

CImg Library is a C++ library for image processing. Prior to commit c3aacf5, the nb_colors field read from the BMP file header is used directly to compute an allocation size without validating it against the remaining file size. A crafted BMP file with a large nb_colors value triggers an out-of-memory condition, crashing any application that uses CImg to load untrusted BMP files. This issue has been patched via commit c3aacf5.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-42146 since 04/24/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version .3.7.5 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch c3aacf5b96ac1e54b7af1957c6737dbf3949f6d3 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• GreycLab

Name

• CImg

License

• open-source

Website

• Product: https://github.com/GreycLab/CImg/

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