diff --git a/src/wallet/crypter.cpp b/src/wallet/crypter.cpp
index d60ce1359d..6a7aae8373 100644
--- a/src/wallet/crypter.cpp
+++ b/src/wallet/crypter.cpp
@@ -198,7 +198,7 @@ bool CCryptoKeyStore::Unlock(const CKeyingMaterial& vMasterKeyIn)
         if (vchCryptedBip39Words.size() || vchCryptedBip39Passphrase.size() || vchCryptedBip39VchSeed.size()) {
             if (!DecryptBip39(vMasterKeyIn)) {
                 LogPrintf("Failed to decrypt bip 39 data");
-                assert(false);
+                return false;
             }
         }
         if (keyPass && keyFail)
diff --git a/src/wallet/test/crypto_tests.cpp b/src/wallet/test/crypto_tests.cpp
index 60bc70281d..ef9a84c90e 100644
--- a/src/wallet/test/crypto_tests.cpp
+++ b/src/wallet/test/crypto_tests.cpp
@@ -13,6 +13,12 @@
 
 BOOST_FIXTURE_TEST_SUITE(wallet_crypto, BasicTestingSetup)
 
+    class TestCryptoKeyStore : public CCryptoKeyStore
+    {
+    public:
+        using CCryptoKeyStore::Unlock;
+    };
+
     class TestCrypter
     {
     public:
@@ -132,4 +138,13 @@ BOOST_FIXTURE_TEST_SUITE(wallet_crypto, BasicTestingSetup)
         }
     }
 
+    BOOST_AUTO_TEST_CASE(unlock_rejects_invalid_encrypted_bip39_data)
+    {
+        TestCryptoKeyStore keystore;
+        keystore.AddCryptedWords(uint256(), std::vector<unsigned char>(1, 0));
+
+        CKeyingMaterial masterKey(WALLET_CRYPTO_KEY_SIZE, 0);
+        BOOST_CHECK(!keystore.Unlock(masterKey));
+    }
+
 BOOST_AUTO_TEST_SUITE_END()