diff --git a/CHANGELOG b/CHANGELOG
index 9d36a50ae..b72acfe89 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
+o Limit verbose -v and debugging -d levels to a maximum of 10. Nmap does not
+  use higher levels internally. [Daniel Miller]
+
 o [NSE] bin.lua is officially deprecated. Lua 5.3, added 2 years ago in Nmap
   7.25BETA2, has native support for binary data packing via string.pack and
   string.unpack. All existing scripts and libraries have been updated.
diff --git a/NmapOps.h b/NmapOps.h
index 7026cfa8e..63b17654e 100644
--- a/NmapOps.h
+++ b/NmapOps.h
@@ -188,7 +188,7 @@ class NmapOps {
   int isr00t;
   /* Whether we have pcap functions (can be false on Windows). */
   bool have_pcap;
-  int debugging;
+  u8 debugging;
   bool resuming;
 
 #define PACKET_SEND_NOPREF 1
@@ -221,7 +221,7 @@ class NmapOps {
   void setVersionTrace(bool vt) { vTrace = vt;  }
   bool openOnly() { return open_only; }
   void setOpenOnly(bool oo) { open_only = oo; }
-  int verbose;
+  u8 verbose;
   /* The requested minimum packet sending rate, or 0.0 if unset. */
   float min_packet_send_rate;
   /* The requested maximum packet sending rate, or 0.0 if unset. */
diff --git a/nmap.cc b/nmap.cc
index 6984c1efd..aea962726 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -968,6 +968,7 @@ void parse_options(int argc, char **argv) {
         } else if (strcmp(long_options[option_index].name, "vv") == 0) {
           /* Compatibility hack ... ugly */
           o.verbose += 2;
+          if (o.verbose > 10) o.verbose = 10;
         } else if (strcmp(long_options[option_index].name, "ff") == 0) {
           o.fragscan += 16;
         } else if (strcmp(long_options[option_index].name, "privileged") == 0) {
@@ -1061,14 +1062,15 @@ void parse_options(int argc, char **argv) {
       break;
     case 'd':
       if (optarg && isdigit(optarg[0])) {
-        o.debugging = o.verbose = atoi(optarg);
+        int i = atoi(optarg);
+        o.debugging = o.verbose = box(0, 10, i);
       } else {
         const char *p;
-        o.debugging++;
-        o.verbose++;
+        if (o.debugging < 10) o.debugging++;
+        if (o.verbose < 10) o.verbose++;
         for (p = optarg != NULL ? optarg : ""; *p == 'd'; p++) {
-          o.debugging++;
-          o.verbose++;
+          if (o.debugging < 10) o.debugging++;
+          if (o.verbose < 10) o.verbose++;
         }
         if (*p != '\0')
           fatal("Invalid argument to -d: \"%s\".", optarg);
@@ -1388,7 +1390,8 @@ void parse_options(int argc, char **argv) {
       break;
     case 'v':
       if (optarg && isdigit(optarg[0])) {
-        o.verbose = atoi(optarg);
+        int i = atoi(optarg);
+        o.verbose = box(0, 10, i);
         if (o.verbose == 0) {
           o.nmap_stdout = fopen(DEVNULL, "w");
           if (!o.nmap_stdout)
@@ -1396,9 +1399,9 @@ void parse_options(int argc, char **argv) {
         }
       } else {
         const char *p;
-        o.verbose++;
+        if (o.verbose < 10) o.verbose++;
         for (p = optarg != NULL ? optarg : ""; *p == 'v'; p++)
-          o.verbose++;
+          if (o.verbose < 10) o.verbose++;
         if (*p != '\0')
           fatal("Invalid argument to -v: \"%s\".", optarg);
       }
diff --git a/nmap_tty.cc b/nmap_tty.cc
index 7cccc0bb1..4ba8ea5ba 100644
--- a/nmap_tty.cc
+++ b/nmap_tty.cc
@@ -320,14 +320,13 @@ bool keyWasPressed()
 
     // printf("You pressed key '%c'!\n", c);
     if (c == 'v') {
-       o.verbose++;
+       if (o.verbose < 10) o.verbose++;
        log_write(LOG_STDOUT, "Verbosity Increased to %d.\n", o.verbose);
     } else if (c == 'V') {
-       if (o.verbose > 0)
-         o.verbose--;
+       if (o.verbose > 0) o.verbose--;
        log_write(LOG_STDOUT, "Verbosity Decreased to %d.\n", o.verbose);
     } else if (c == 'd') {
-       o.debugging++;
+       if (o.debugging < 10) o.debugging++;
        log_write(LOG_STDOUT, "Debugging Increased to %d.\n", o.debugging);
     } else if (c == 'D') {
        if (o.debugging > 0) o.debugging--;