diff --git a/tools/grib_to_netcdf.c b/tools/grib_to_netcdf.c
index ec685d62a..afdda6681 100644
--- a/tools/grib_to_netcdf.c
+++ b/tools/grib_to_netcdf.c
@@ -27,7 +27,7 @@
 const char* grib_tool_description = "Convert a GRIB file to netCDF format.";
 const char* grib_tool_name = "grib_to_netcdf";
 const char* grib_tool_usage = "[options] grib_file grib_file ... ";
-static char argvString[2048];
+static char argvString[2048] = {0,};
 
 /*=====================================================================*/
 
@@ -3978,7 +3978,11 @@ int main(int argc, char *argv[])
     int i, ret = 0;
 
     /* GRIB-413: Collect all program arguments into a string */
+    const size_t maxLen = sizeof(argvString);
+    size_t currLen = 0;
     for (i=0; i<argc; ++i) {
+        currLen += strlen(argv[i]);
+        if ( currLen >= maxLen-1 ) break;
         strcat(argvString, argv[i]);
         if (i != argc-1) strcat(argvString, " ");
     }