In was found that in the Linux kernel, in vmw_surface_define_ioctl() function in ‘drivers/gpu/drm/vmwgfx/vmwgfx_surface.c’ file, a ‘num_sizes’ parameter is assigned a user-controlled value which is not checked if it is zero. This is used in a call to kmalloc() and later leads to dereferencing ZERO_SIZE_PTR, which in turn leads to a GPF and possibly to a kernel panic.