diff --git a/src/backend/helpers/yaml_set_helpers.h b/src/backend/helpers/yaml_set_helpers.h
index de63209e..35a686b0 100644
--- a/src/backend/helpers/yaml_set_helpers.h
+++ b/src/backend/helpers/yaml_set_helpers.h
@@ -47,7 +47,8 @@ namespace YAML {
 
             rhs.clear();
             for (const auto &element : node) {
-                rhs.insert(element.template as<T>());
+                if (!rhs.insert(element.template as<T>()).second)
+                    return false;
             }
             return true;
         }
@@ -80,7 +81,8 @@ namespace YAML {
 
             rhs.clear();
             for (const auto &element : node) {
-                rhs.insert(element.template as<T>());
+                if (!rhs.insert(element.template as<T>()).second)
+                    return false;
             }
             return true;
         }
diff --git a/src/tests/backend/helpers/test_yaml_set_helpers.h b/src/tests/backend/helpers/test_yaml_set_helpers.h
index b006b6a3..cfe70178 100644
--- a/src/tests/backend/helpers/test_yaml_set_helpers.h
+++ b/src/tests/backend/helpers/test_yaml_set_helpers.h
@@ -46,6 +46,9 @@ TEST(set, YamlDecode) {
     EXPECT_EQ(stringSet.begin(), stringSet.find("a"));
     EXPECT_EQ(++stringSet.begin(), stringSet.find("b"));
     EXPECT_EQ(--stringSet.end(), stringSet.find("c"));
+
+    node = YAML::Load("[a, b, c, c]");
+    EXPECT_ANY_THROW(node.as<std::set<std::string>>());
 }
 
 TEST(set, YamlEmitter) {
@@ -82,6 +85,9 @@ TEST(unordered_set, YAMLDecode) {
     EXPECT_EQ(1, stringSet.count("a"));
     EXPECT_EQ(1, stringSet.count("b"));
     EXPECT_EQ(1, stringSet.count("c"));
+
+    node = YAML::Load("[a, b, c, c]");
+    EXPECT_ANY_THROW(node.as<std::unordered_set<std::string>>());
 }
 
 bool sequenceOf(const char val1,