Denial of Service Vulnerability in Gumlet php-image-resize

The Gumlet php-image-resize library, specifically versions prior to 3.0.1, contains a denial of service (DoS) vulnerability. The flaw exists within the ImageResize constructor located in 'lib/ImageResize.php'. The component fails to enforce pixel count limits when passing images to the PHP GD library's 'imagecreatefrom*' functions. A remote attacker can exploit this by uploading a small, highly compressed image file that, upon decompression by the GD library, expands into an excessively large bitmap in memory. This process rapidly exhausts the PHP memory limit, causing the worker process to crash or terminate. This vulnerability impacts applications relying on this library for server-side image manipulation and is particularly dangerous in environments that allow unauthenticated or user-supplied image uploads.

Impact

Successful exploitation results in the immediate termination of the PHP worker process handling the request. Repeated exploitation can lead to a complete denial of service for the web application, exhausting server resources and preventing legitimate users from accessing services.

Recommendation

• Upgrade the 'Gumlet php-image-resize' library to version 3.0.1 or later immediately to include pixel limit enforcement.
• In environments where immediate patching is not possible, implement an upstream WAF rule to validate image dimensions before passing files to the PHP backend.
• Configure PHP memory limits (memory_limit) to prevent a single request from exhausting total system RAM, though this does not mitigate the application-level worker crash.