diff --git a/examples/pn53x-tamashell.c b/examples/pn53x-tamashell.c
index eac9993..42a06ff 100644
--- a/examples/pn53x-tamashell.c
+++ b/examples/pn53x-tamashell.c
@@ -159,7 +159,7 @@ int main(int argc, const char *argv[])
       while (isspace(cmd[offset])) {
         offset++;
       }
-      sscanf(cmd + offset, "%d", &s);
+      sscanf(cmd + offset, "%10d", &s);
       printf("Pause for %i msecs\n", s);
       if (s > 0) {
         sleep(s * SUSP_TIME);
diff --git a/libnfc/drivers/acr122_pcsc.c b/libnfc/drivers/acr122_pcsc.c
index e24e425..6a9151a 100644
--- a/libnfc/drivers/acr122_pcsc.c
+++ b/libnfc/drivers/acr122_pcsc.c
@@ -258,7 +258,7 @@ acr122_pcsc_open(const nfc_context *context, const nfc_connstring connstring)
   if (strlen(ndd.pcsc_device_name) < 5) { // We can assume it's a reader ID as pcsc_name always ends with "NN NN"
     // Device was not specified, only ID, retrieve it
     size_t index;
-    if (sscanf(ndd.pcsc_device_name, "%lu", &index) != 1)
+    if (sscanf(ndd.pcsc_device_name, "%4lu", &index) != 1)
       return NULL;
     nfc_connstring *ncs = malloc(sizeof(nfc_connstring) * (index + 1));
     if (!ncs) {
diff --git a/libnfc/drivers/acr122s.c b/libnfc/drivers/acr122s.c
index 0b19d32..c84a8da 100644
--- a/libnfc/drivers/acr122s.c
+++ b/libnfc/drivers/acr122s.c
@@ -438,7 +438,7 @@ acr122s_connstring_decode(const nfc_connstring connstring, struct acr122s_descri
     return 2;
   }
   unsigned long speed;
-  if (sscanf(speed_s, "%lu", &speed) != 1) {
+  if (sscanf(speed_s, "%10lu", &speed) != 1) {
     // speed_s is not a number
     free(cs);
     return 2;
diff --git a/libnfc/drivers/arygon.c b/libnfc/drivers/arygon.c
index a788807..315fc0b 100644
--- a/libnfc/drivers/arygon.c
+++ b/libnfc/drivers/arygon.c
@@ -207,7 +207,7 @@ arygon_connstring_decode(const nfc_connstring connstring, struct arygon_descript
     return 2;
   }
   unsigned long speed;
-  if (sscanf(speed_s, "%lu", &speed) != 1) {
+  if (sscanf(speed_s, "%10lu", &speed) != 1) {
     // speed_s is not a number
     free(cs);
     return 2;
@@ -519,7 +519,9 @@ arygon_firmware(nfc_device *pnd, char *str)
   if (0 == memcmp(abtRx, arygon_error_none, 6)) {
     uint8_t *p = abtRx + 6;
     unsigned int szData;
-    sscanf((const char *)p, "%02x%s", &szData, p);
+    sscanf((const char *)p, "%02x%9s", &szData, p);
+    if (szData > 9)
+      szData = 9;
     memcpy(str, p, szData);
     *(str + szData) = '\0';
   }
diff --git a/libnfc/drivers/pn532_uart.c b/libnfc/drivers/pn532_uart.c
index f7b8867..4ae4380 100644
--- a/libnfc/drivers/pn532_uart.c
+++ b/libnfc/drivers/pn532_uart.c
@@ -184,7 +184,7 @@ pn532_connstring_decode(const nfc_connstring connstring, struct pn532_uart_descr
     return 2;
   }
   unsigned long speed;
-  if (sscanf(speed_s, "%lu", &speed) != 1) {
+  if (sscanf(speed_s, "%10lu", &speed) != 1) {
     // speed_s is not a number
     free(cs);
     return 2;
diff --git a/utils/nfc-relay-picc.c b/utils/nfc-relay-picc.c
index 1659c4d..43988e5 100644
--- a/utils/nfc-relay-picc.c
+++ b/utils/nfc-relay-picc.c
@@ -173,7 +173,7 @@ main(int argc, char *argv[])
       printf("INFO: %s\n", "Swapping devices.");
       swap_devices = true;
     } else if (0 == strcmp(argv[arg], "-n")) {
-      if (++arg == argc || (sscanf(argv[arg], "%i", &waiting_time) < 1)) {
+      if (++arg == argc || (sscanf(argv[arg], "%10i", &waiting_time) < 1)) {
         ERR("Missing or wrong waiting time value: %s.", argv[arg]);
         print_usage(argv);
         exit(EXIT_FAILURE);