diff --git a/Changelog.md b/Changelog.md
index 39c79ec22..d271f2f66 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,8 @@
 ### 0.4.26 (unreleased)
 
+Important Bugfixes:
+ * Code Generator: Fix initialization routine of uninitialized internal function pointers in constructor context.
+
 Bugfixes:
  * General: Split rule list such that JavaScript environments with small stacks can use the compiler.
 
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index d9f172639..6cb6fcff5 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -1060,6 +1060,14 @@ void CompilerUtils::pushZeroValue(Type const& _type)
 			m_context << m_context.lowLevelFunctionTag("$invalidFunction", 0, 0, [](CompilerContext& _context) {
 				_context.appendInvalid();
 			});
+			if (CompilerContext* runCon = m_context.runtimeContext())
+			{
+				leftShiftNumberOnStack(32);
+				m_context << runCon->lowLevelFunctionTag("$invalidFunction", 0, 0, [](CompilerContext& _context) {
+					_context.appendInvalid();
+				}).toSubAssemblyTag(m_context.runtimeSub());
+				m_context << Instruction::OR;
+			}
 			return;
 		}
 	}
diff --git a/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidInConstructor.sol b/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidInConstructor.sol
new file mode 100644
index 000000000..26c02f3e3
--- /dev/null
+++ b/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidInConstructor.sol
@@ -0,0 +1,23 @@
+contract C {
+
+  function() internal storedFn;
+
+  bool flag;
+
+  constructor() public {
+    if (!flag) {
+      flag = true;
+      function() internal invalid;
+      storedFn = invalid;
+      invalid();
+    }
+  }
+  function f() public pure {}
+}
+contract Test {
+  function f() public {
+    new C();
+  }
+}
+// ----
+// f() -> FAILURE
diff --git a/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidStoredInConstructor.sol b/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidStoredInConstructor.sol
new file mode 100644
index 000000000..710348a1a
--- /dev/null
+++ b/test/libsolidity/semanticTests/uninitializedFunctionPointer/invalidStoredInConstructor.sol
@@ -0,0 +1,23 @@
+contract C {
+
+  function() internal storedFn;
+
+  bool flag;
+
+  constructor() public {
+    if (!flag) {
+      flag = true;
+      function() internal invalid;
+      storedFn = invalid;
+      storedFn();
+    }
+  }
+  function f() public pure {}
+}
+contract Test {
+  function f() public {
+    new C();
+  }
+}
+// ----
+// f() -> FAILURE
diff --git a/test/libsolidity/semanticTests/uninitializedFunctionPointer/storeInConstructor.sol b/test/libsolidity/semanticTests/uninitializedFunctionPointer/storeInConstructor.sol
new file mode 100644
index 000000000..8a11832c8
--- /dev/null
+++ b/test/libsolidity/semanticTests/uninitializedFunctionPointer/storeInConstructor.sol
@@ -0,0 +1,19 @@
+contract InvalidTest {
+
+  function() internal storedFn;
+
+  bool flag;
+
+  constructor() public {
+    function() internal invalid;
+    storedFn = invalid;
+  }
+  function f() public returns (uint) {
+    if (flag) return 2;
+    flag = true;
+    storedFn();
+  }
+}
+// ----
+// f() -> FAILURE
+// f() -> FAILURE