ext/markdown/autolink.c in github-markdown-0.5.2 vs ext/markdown/autolink.c in github-markdown-0.5.3

@@ -233,10 +233,11 @@
 			np++;
 		else if (c != '-' && c != '_')
 			break;
 	}
 
-	if (link_end < 2 || nb != 1 || np == 0)
+	if (link_end < 2 || nb != 1 || np == 0 ||
+		!isalpha(data[link_end - 1]))
 		return 0;
 
 	link_end = autolink_delim(data, link_end, max_rewind, size);
 
 	if (link_end == 0)