Came up with a working patch based on Daryl's post.
Latest cmsb version in same file (upload_functions.php) and function (showUploadPreview) Daryl referenced.
Before
// output preview html
Add
// display image preview for svg image file type
if (preg_match("/\.(svg)$/i", $uploadRecord['urlPath'])) {
$bestSrc = $uploadRecord['urlPath'];
$bestWidth = "50";
$bestHeight = "50";
}
Seems those three strings aren't being set for svg's since their width and height values are saved as 0 in the uploads table.