A heap-based buffer overflow vulnerability exists in the GIMP DDS file parser. It occurs when a crafted DDS file declares a D3D9 pixel format but specifies a lower bits-per-pixel value, causing the loader to allocate an undersized heap buffer. This leads to a write beyond the buffer boundary, potentially corrupting heap metadata and enabling code execution. The vulnerability is triggered when opening a malicious DDS file with GIMP. Users should avoid opening untrusted DDS files or consider removing GIMP if not needed.