PdfFormatProvider provider = new PdfFormatProvider();
this.pdfDocument = provider.Import(memory);

foreach (var page in this.pdfDocument.Pages.ToList())
{
    List<Link> links = page.Annotations.Where(a => a.Type == AnnotationType.Link).Select(a => a as Link).ToList();
    foreach (var link in links)
    {
        Uri uri;
        UriAction uriAction = link.Action as UriAction;

        try
        {
            uri = uriAction.Uri;
        }
        catch (UriFormatException)
        {
            page.Annotations.Remove(link);
        }
    }
}