Gdk-pixbuf: gdk-pixbuf: heap out-of-bounds read in uncompress() via crafted icns rle block

A flaw was found in gdk-pixbuf. This vulnerability allows a remote attacker to cause a heap out-of-bounds read by providing a specially crafted Apple Icon Image (.icns) file. The uncompress() function, which handles RLE-encoded ICNS icon data, fails to validate the source buffer's boundaries during decompression. This can lead to a denial of service, where the application crashes, or to information disclosure, potentially revealing sensitive data from adjacent memory.