diff -up cracklib-2.9.6/lib/packlib.c.lookup cracklib-2.9.6/lib/packlib.c
--- cracklib-2.9.6/lib/packlib.c.lookup	2018-10-10 14:19:06.988958835 +0200
+++ cracklib-2.9.6/lib/packlib.c	2018-11-26 16:04:34.648256614 +0100
@@ -585,12 +585,11 @@ fprintf(stderr, "look for (%s)\n", strin
     fprintf(stderr, "---- %lu, %lu ----\n", lwm, hwm);
 #endif
 
-    middle = lwm + ((hwm - lwm + 1) / 2);
-
     for (;;)
     {
 	int cmp;
 
+	middle = lwm + ((hwm - lwm + 1) / 2);
 
 #if DEBUG
 	fprintf(stderr, "lwm = %lu,  middle = %lu,  hwm = %lu\n", lwm, middle, hwm);
@@ -617,24 +616,28 @@ fprintf(stderr, "look for (%s)\n", strin
 	    return(middle);
         }
 
-        if (middle == hwm)
-        {
-#if DEBUG
-		fprintf(stderr, "at terminal subdivision, stopping search\n");
-#endif
-		break;
-        }
-
 	if (cmp < 0)
 	{
-	    hwm = middle;
-	    middle = lwm + ((hwm - lwm ) / 2);
-	}
+	    if (middle == lwm)
+	    {
+#if DEBUG 
+		fprintf(stderr, "at terminal subdivision from right, stopping search\n");
+#endif
+		break;
+	    }
+	    hwm = middle - 1;
+	} 
 	else if (cmp > 0)
 	{
-	    lwm = middle;
-	    middle = lwm + ((hwm - lwm + 1) / 2);
-	}
+	    if (middle == hwm)
+	    {
+#if DEBUG 
+		fprintf(stderr, "at terminal subdivision from left, stopping search\n");
+#endif
+		break;
+	    }
+	    lwm = middle + 1;
+	} 
     }
 
     return (PW_WORDS(pwp));