CVE-2026-77118

Name of the Vulnerable Software and Affected Versions GraphicsMagick (affected versions not specified)

Description A heap out-of-bounds write exists in the Photo CD (PCD) decoder. In the DecodeImage() function (coders/pcd.c), the Huffman delta loop advances its output pointer using q++ after every decoded delta without verifying it against the end of the heap-allocated luma/chroma plane buffers. The pointer is only repositioned when a sync marker introduces a new plane or row; otherwise, the run length is determined solely by the input. A specially crafted PCD file can position the pointer near the end of a plane and provide a long run of deltas without sync markers, causing the pointer to move past the allocation boundary and write into adjacent heap memory. This can occur when processing untrusted PCD files via gm convert, gm identify, or any application linked against libGraphicsMagick.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.