diff --git a/src/Neo/Network/P2P/Payloads/Transaction.cs b/src/Neo/Network/P2P/Payloads/Transaction.cs
index 69a1b179e9..16417beb43 100644
--- a/src/Neo/Network/P2P/Payloads/Transaction.cs
+++ b/src/Neo/Network/P2P/Payloads/Transaction.cs
@@ -458,6 +458,7 @@ public virtual VerifyResult VerifyStateIndependent(ProtocolSettings settings)
 
         public StackItem ToStackItem(ReferenceCounter referenceCounter)
         {
+            if (_signers == null || _signers.Length == 0) throw new ArgumentException("Sender is not specified in the transaction.");
             return new Array(referenceCounter, new StackItem[]
             {
                 // Computed properties
diff --git a/src/Neo/SmartContract/ApplicationEngine.Runtime.cs b/src/Neo/SmartContract/ApplicationEngine.Runtime.cs
index 4314952eec..293b245bd7 100644
--- a/src/Neo/SmartContract/ApplicationEngine.Runtime.cs
+++ b/src/Neo/SmartContract/ApplicationEngine.Runtime.cs
@@ -327,9 +327,16 @@ protected internal BigInteger GetRandom()
         /// <param name="state">The message of the log.</param>
         protected internal void RuntimeLog(byte[] state)
         {
-            if (state.Length > MaxNotificationSize) throw new ArgumentException(null, nameof(state));
-            string message = Utility.StrictUTF8.GetString(state);
-            Log?.Invoke(this, new LogEventArgs(ScriptContainer, CurrentScriptHash, message));
+            if (state.Length > MaxNotificationSize) throw new ArgumentException("Message is too long.", nameof(state));
+            try
+            {
+                string message = Utility.StrictUTF8.GetString(state);
+                Log?.Invoke(this, new LogEventArgs(ScriptContainer, CurrentScriptHash, message));
+            }
+            catch
+            {
+                throw new ArgumentException("Failed to convert byte array to string: Invalid or non-printable UTF-8 sequence detected.", nameof(state));
+            }
         }
 
         /// <summary>
diff --git a/tests/Neo.UnitTests/SmartContract/UT_ApplicationEngine.Runtime.cs b/tests/Neo.UnitTests/SmartContract/UT_ApplicationEngine.Runtime.cs
index 80bbf45e9d..75e6e7b6da 100644
--- a/tests/Neo.UnitTests/SmartContract/UT_ApplicationEngine.Runtime.cs
+++ b/tests/Neo.UnitTests/SmartContract/UT_ApplicationEngine.Runtime.cs
@@ -175,5 +175,17 @@ public void TestGetRandomDifferentBlock()
             rand_4.Should().NotBe(rand_9);
             rand_5.Should().NotBe(rand_10);
         }
+
+        [TestMethod]
+        public void TestInvalidUtf8LogMessage()
+        {
+            var tx_1 = TestUtils.GetTransaction(UInt160.Zero);
+            using var engine = ApplicationEngine.Create(TriggerType.Application, tx_1, null, TestBlockchain.TheNeoSystem.GenesisBlock, settings: TestBlockchain.TheNeoSystem.Settings, gas: 1100_00000000);
+            var msg = new byte[]
+            {
+                68, 216, 160, 6, 89, 102, 86, 72, 37, 15, 132, 45, 76, 221, 170, 21, 128, 51, 34, 168, 205, 56, 10, 228, 51, 114, 4, 218, 245, 155, 172, 132
+            };
+            Assert.ThrowsException<ArgumentException>(() => engine.RuntimeLog(msg));
+        }
     }
 }