diff --git a/src/psbt.h b/src/psbt.h
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -101,6 +101,7 @@
 
     template <typename Stream> inline void Unserialize(Stream &s) {
         // Read loop
+        bool found_sep = false;
         while (!s.empty()) {
             // Read
             std::vector<uint8_t> key;
@@ -110,7 +111,8 @@
             // This is a special case for key lengths 0 as those are not allowed
             // (except for separator)
             if (key.empty()) {
-                return;
+                found_sep = true;
+                break;
             }
 
             // First byte of key is the type
@@ -210,6 +212,10 @@
                     break;
             }
         }
+        if (!found_sep) {
+            throw std::ios_base::failure(
+                "Separator is missing at the end of an input map");
+        }
     }
 
     template <typename Stream> PSBTInput(deserialize_type, Stream &s) {
@@ -251,6 +257,7 @@
 
     template <typename Stream> inline void Unserialize(Stream &s) {
         // Read loop
+        bool found_sep = false;
         while (!s.empty()) {
             // Read
             std::vector<uint8_t> key;
@@ -260,7 +267,8 @@
             // This is a special case for key lengths 0 as those are not allowed
             // (except for separator)
             if (key.empty()) {
-                return;
+                found_sep = true;
+                break;
             }
 
             // First byte of key is the type
@@ -300,6 +308,11 @@
                 }
             }
         }
+
+        if (!found_sep) {
+            throw std::ios_base::failure(
+                "Separator is missing at the end of an output map");
+        }
     }
 
     template <typename Stream> PSBTOutput(deserialize_type, Stream &s) {
@@ -380,6 +393,7 @@
         }
 
         // Read global data
+        bool found_sep = false;
         while (!s.empty()) {
             // Read
             std::vector<uint8_t> key;
@@ -389,6 +403,7 @@
             // This is a special case for key lengths 0 as those are not allowed
             // (except for separator)
             if (key.empty()) {
+                found_sep = true;
                 break;
             }
 
@@ -433,6 +448,11 @@
             }
         }
 
+        if (!found_sep) {
+            throw std::ios_base::failure(
+                "Separator is missing at the end of the global map");
+        }
+
         // Make sure that we got an unsigned tx
         if (!tx) {
             throw std::ios_base::failure(
diff --git a/test/functional/data/rpc_psbt.json b/test/functional/data/rpc_psbt.json
--- a/test/functional/data/rpc_psbt.json
+++ b/test/functional/data/rpc_psbt.json
@@ -13,7 +13,9 @@
         "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",
         "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",
         "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAEAHwDKmjsAAAAAFgAU0tlLZK4IWH7vyO6xh8YB6Tn5A3wCAwAEQQAAAAABABYAFGLp6YL/803YI5YQMWsJDNKjt0fLAAEAIgAgh2utgy8dFoAV7UEjKp6mWhgV2e8TwO+HWfZLWysnimUBASVRIQO3ziOgHFtL8ApkJTfN+rsxW2aDMoZ0eO9RMJ0r1X+Kh1GuAA==",
-        "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAACAAAWABRi6emC//NN2COWEDFrCQzSo7dHywACAAAiACCHa62DLx0WgBXtQSMqnqZaGBXZ7xPA74dZ9ktbKyeKZQEBJVEhA7fOI6AcW0vwCmQlN836uzFbZoMyhnR471EwnSvVf4qHUa4A"
+        "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAACAAAWABRi6emC//NN2COWEDFrCQzSo7dHywACAAAiACCHa62DLx0WgBXtQSMqnqZaGBXZ7xPA74dZ9ktbKyeKZQEBJVEhA7fOI6AcW0vwCmQlN836uzFbZoMyhnR471EwnSvVf4qHUa4A",
+        "cHNidP8BAHMCAAAAATAa6YblFqHsisW0vGVz0y+DtGXiOtdhZ9aLOOcwtNvbAAAAAAD/////AnR7AQAAAAAAF6kUA6oXrogrXQ1Usl1jEE5P/s57nqKHYEOZOwAAAAAXqRS5IbG6b3IuS/qDtlV6MTmYakLsg4cAAAAAAAEBHwDKmjsAAAAAFgAU0tlLZK4IWH7vyO6xh8YB6Tn5A3wAAQAWABRi6emC//NN2COWEDFrCQzSo7dHywABACIAIIdrrYMvHRaAFe1BIyqeploYFdnvE8Dvh1n2S1srJ4plIQEAJVEhA7fOI6AcW0vwCmQlN836uzFbZoMyhnR471EwnSvVf4qHUa4A",
+        "cHNidP8BAHMCAAAAAbiWoY6pOQepFsEGhUPXaulX9rvye2NH+NrdlAHg+WgpAQAAAAD/////AkBLTAAAAAAAF6kUqWwXCcLM5BN2zoNqMNT5qMlIi7+HQEtMAAAAAAAXqRSVF/in2XNxAlN1OSxkyp0z+Wtg2YcAAAAAAAEBIBNssgAAAAAAF6kUamsvautR8hRlMRY6OKNTx03DK96HAQcXFgAUo8u1LWpHprjt/uENAwBpGZD0UH0BCGsCRzBEAiAONfH3DYiw67ZbylrsxCF/XXpVwyWBRgofyRbPslzvwgIgIKCsWw5sHSIPh1icNvcVLZLHWj6NA7Dk+4Os2pOnMbQBIQPGStfYHPtyhpV7zIWtn0Q4GXv5gK1zy/tnJ+cBXu4iiwABABYAFMwmJQEz+HDpBEEabxJ5PogPsqZRAAEAFgAUyCrGc3h3FYCmiIspbv2pSTKZ5jU"
     ],
     "valid" : [
         "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFNDFmQPFusKGh2DpD9UhpGZap2UgiKwA4fUFAAAAABepFDVF5uM7gyxHBQ8k0+65PJwDlIvHh7MuEwAAAQAiAMLrCwAAAAAZdqkUhc/xCX/Z4Ai7NK9wnGIZeziXikiIrAAAAA==",