diff --git a/internal/platform/bluetooth_utils.cc b/internal/platform/bluetooth_utils.cc
index cb512acf..b5d26c72 100644
--- a/internal/platform/bluetooth_utils.cc
+++ b/internal/platform/bluetooth_utils.cc
@@ -14,6 +14,8 @@
 
 #include "internal/platform/bluetooth_utils.h"
 
+#include <algorithm>
+
 #include "absl/strings/escaping.h"
 #include "absl/strings/str_format.h"
 
@@ -39,17 +41,15 @@ std::string BluetoothUtils::ToString(const ByteArray& bluetooth_mac_address) {
 ByteArray BluetoothUtils::FromString(absl::string_view bluetooth_mac_address) {
   std::string bt_mac_address(bluetooth_mac_address);
 
-  // Remove the colon delimiters.
   bt_mac_address.erase(
       std::remove(bt_mac_address.begin(), bt_mac_address.end(), ':'),
       bt_mac_address.end());
 
-  // If the bluetooth mac address is invalid (wrong size), return a null byte
-  // array.
-  if (bt_mac_address.length() != kBluetoothMacAddressLength * 2) {
+  if (bt_mac_address.length() != kBluetoothMacAddressLength * 2 ||
+      !std::all_of(bt_mac_address.begin(), bt_mac_address.end(),
+                   absl::ascii_isxdigit)) {
     return ByteArray();
   }
-  // Convert to bytes. If MAC Address bytes are unset, return a null byte array.
   auto bt_mac_address_string(absl::HexStringToBytes(bt_mac_address));
   auto bt_mac_address_bytes =
       ByteArray(bt_mac_address_string.data(), bt_mac_address_string.size());
diff --git a/internal/platform/bluetooth_utils_test.cc b/internal/platform/bluetooth_utils_test.cc
index f2fbab63..82ffea5e 100644
--- a/internal/platform/bluetooth_utils_test.cc
+++ b/internal/platform/bluetooth_utils_test.cc
@@ -82,6 +82,10 @@ TEST(BluetoothUtilsTest, InvalidStringReturnsEmptyByteArray) {
   std::string bad_bt_mac_address_4 = "BLUETOOTHCHIP";
   bytes_result = BluetoothUtils::FromString(bad_bt_mac_address_4);
   EXPECT_TRUE(bytes_result.Empty());
+
+  std::string bad_bt_mac_address_5 = "G1:F2:F3:F4:F5:F6";
+  bytes_result = BluetoothUtils::FromString(bad_bt_mac_address_5);
+  EXPECT_TRUE(bytes_result.Empty());
 }
 
 TEST(BluetoothUtilsTest, FromNumber) {