Gimp: integer overflow when generating a thumbnail preview for a psd file

A flaw was found in the file-psd plugin in GIMP. When generating a thumbnail preview for a specially crafted PSD (Photoshop Document) image file, an integer overflow occurs during the multiplication of values from an embedded JPEG header. This leads to an undersized heap allocation, resulting in a heap-based buffer overflow when the image data is decoded. This buffer overflow corrupts adjacent heap objects, allowing for a controlled memory write that can result in an application crash or arbitrary code execution.