diff --git a/src/Network/fgcom.cxx b/src/Network/fgcom.cxx
index 1e9d7a5f8..b14214b60 100644
--- a/src/Network/fgcom.cxx
+++ b/src/Network/fgcom.cxx
@@ -694,17 +694,17 @@ std::string FGCom::computePhoneNumber(const double& freq, const std::string& ica
   char tmp[5];
 
   /*Convert ICAO to ASCII */
-  sprintf( tmp, "%4s", icao.c_str() );
+  snprintf(tmp, 5, "%4s", icao.c_str());
 
   /*Built the phone number */
-  sprintf( exten,
+  snprintf(exten, 32,
            "%02d%02d%02d%02d%02d%06d",
            01,
            tmp[0],
-	   tmp[1],
+           tmp[1],
            tmp[2],
            tmp[3],
-	   (int) (freq * 1000 + 0.5) );
+           (int)(freq * 1000 + 0.5));
   exten[16] = '\0';
 
   snprintf( phoneNumber,
diff --git a/src/Network/garmin.cxx b/src/Network/garmin.cxx
index ac517b695..7283b0773 100644
--- a/src/Network/garmin.cxx
+++ b/src/Network/garmin.cxx
@@ -66,9 +66,9 @@ bool FGGarmin::gen_message()
 
         // $PGRMZ,AAAA.A,F,T*XX
         if (mMetric)
-            sprintf( nmea, "$PGRMZ,%.1f,M,3", altitude_ft * SG_FEET_TO_METER );
+            snprintf(nmea, 256, "$PGRMZ,%.1f,M,3", altitude_ft * SG_FEET_TO_METER);
         else
-            sprintf( nmea, "$PGRMZ,%.1f,F,3", altitude_ft );
+            snprintf(nmea, 256, "$PGRMZ,%.1f,F,3", altitude_ft);
         add_with_checksum(nmea, 256);
     }