diff -p -up sane-backends-1.0.20/backend/rts8891.c.strformat sane-backends-1.0.20/backend/rts8891.c
--- sane-backends-1.0.20/backend/rts8891.c.strformat	2009-04-30 15:15:20.000000000 +0200
+++ sane-backends-1.0.20/backend/rts8891.c	2009-09-28 14:00:28.000000000 +0200
@@ -3751,7 +3751,7 @@ init_device (struct Rts8891_Device *dev)
       for (i = 0; i < dev->reg_count; i++)
 	sprintf (message + strlen (message), "0x%02x ", dev->regs[i]);
       sprintf (message + strlen (message), "\n");
-      DBG (DBG_io2, message);
+      DBG (DBG_io2, "%s", message);
     }
 
   /* initial sensor guess */
--- sane-backends-1.0.22/frontend/scanimage.c.str	2011-04-01 10:42:12.000000000 +0200
+++ sane-backends-1.0.22/frontend/scanimage.c	2011-04-01 10:42:36.000000000 +0200
@@ -1891,7 +1891,7 @@
 				printf (start, int_arg);
 				break;
 			      case 0:
-				printf (start);
+				printf ("%s", start);
 				break;
 			      }
 			    *percent = cc;
@@ -1905,7 +1905,7 @@
 			  }
 		      }
 		    if (*start)
-		      printf (start);
+		      printf ("%s",start);
 		  }
 	      }
 	    if (i == 0 && ch != 'f')