diff --git a/CHANGELOG b/CHANGELOG
index 11ba1f6..f7081c8 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
-# 1.0.148
+# Current
 
+## Security:
+- See CVE-2023-27390. Check there are no "self" message.
+
+## Build
 - Set MSVC_RUNTIME_LIBRARY to /MT for static builds
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a3fa093..74eb999 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,11 @@ project(Diagon
 
 option(DIAGON_BUILD_TESTS "Set to ON to build tests" OFF)
 option(DIAGON_BUILD_TESTS_FUZZER "Set to ON to enable fuzzing" OFF)
+option(DIAGON_ASAN "Set to ON to enable address sanitizer" OFF)
+option(DIAGON_LSAN "Set to ON to enable leak sanitizer" OFF)
+option(DIAGON_MSAN "Set to ON to enable memory sanitizer" OFF)
+option(DIAGON_TSAN "Set to ON to enable thread sanitizer" OFF)
+option(DIAGON_UBSAN "Set to ON to enable undefined behavior sanitizer" OFF)
 
 include(FetchContent)
 set(FETCHCONTENT_QUIET FALSE)
diff --git a/cmake/diagon_fuzzer.cmake b/cmake/diagon_fuzzer.cmake
index 8c42b3f..0670fac 100644
--- a/cmake/diagon_fuzzer.cmake
+++ b/cmake/diagon_fuzzer.cmake
@@ -2,7 +2,7 @@ set(CMAKE_C_COMPILER clang)
 set(CMAKE_CXX_COMPILER clang++)
 
 add_executable(fuzzer src/fuzzer.cpp)
-target_compile_options(fuzzer PRIVATE -fsanitize=fuzzer,address)
-target_link_libraries(fuzzer PRIVATE -fsanitize=fuzzer,address)
+target_compile_options(fuzzer PRIVATE -fsanitize=fuzzer)
+target_link_libraries(fuzzer PRIVATE -fsanitize=fuzzer)
 target_link_libraries(fuzzer PRIVATE diagon_lib)
 target_set_common(fuzzer)
diff --git a/cmake/diagon_test.cmake b/cmake/diagon_test.cmake
index b87a329..bcb436f 100644
--- a/cmake/diagon_test.cmake
+++ b/cmake/diagon_test.cmake
@@ -1,3 +1,42 @@
 add_executable(input_output_test src/input_output_test.cpp)
 target_link_libraries(input_output_test diagon_lib)
 target_set_common(input_output_test)
+
+option(DIAGON_ASAN "Set to ON to enable address sanitizer" OFF)
+option(DIAGON_LSAN "Set to ON to enable leak sanitizer" OFF)
+option(DIAGON_MSAN "Set to ON to enable memory sanitizer" OFF)
+option(DIAGON_TSAN "Set to ON to enable thread sanitizer" OFF)
+option(DIAGON_UBSAN "Set to ON to enable undefined behavior sanitizer" OFF)
+if (NOT CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  return()
+endif()
+
+# Add ASAN
+if (DIAGON_ASAN)
+  add_compile_options(-fsanitize=address)
+  add_link_options(-fsanitize=address)
+endif()
+
+# Add LSAN
+if (DIAGON_LSAN)
+  add_compile_options(-fsanitize=leak)
+  add_link_options(-fsanitize=leak)
+endif()
+
+# Add MSAN
+if (DIAGON_MSAN)
+  add_compile_options(-fsanitize=memory)
+  add_link_options(-fsanitize=memory)
+endif()
+
+# Add TSAN
+if (DIAGON_TSAN)
+  add_compile_options(-fsanitize=thread)
+  add_link_options(-fsanitize=thread)
+endif()
+
+# Add UBSAN
+if (DIAGON_UBSAN)
+  add_compile_options(-fsanitize=undefined)
+  add_link_options(-fsanitize=undefined)
+endif()
diff --git a/src/input_output_test.cpp b/src/input_output_test.cpp
index 6331710..01ca1ca 100644
--- a/src/input_output_test.cpp
+++ b/src/input_output_test.cpp
@@ -58,13 +58,14 @@ int main(int, const char**) {
         continue;
       }
 
+      // std::cout << "  [RUN ] " << test.path() << std::endl;
       std::string input = ReadFile(test.path() / "input");
       std::string output = ReadFile(test.path() / "output");
 
       std::string output_computed = translator->Translate(input, options);
 
       if (output_computed == output) {
-        //std::cout << "  [PASS] " << test.path() << std::endl;
+        std::cout << "  [PASS] " << test.path() << std::endl;
       } else {
         std::cout << "  [FAIL] " << test.path() << std::endl;
         std::cout << "---[Output]------------------" << std::endl;
diff --git a/src/translator/sequence/Sequence.cpp b/src/translator/sequence/Sequence.cpp
index 9163875..cda1cf1 100644
--- a/src/translator/sequence/Sequence.cpp
+++ b/src/translator/sequence/Sequence.cpp
@@ -288,6 +288,7 @@ std::string Sequence::Translate(const std::string& input,
   UniformizeInternalRepresentation();
   if (actors.size() == 0)
     return "";
+
   SplitByBackslashN();
   Layout();
   return Draw();
@@ -361,7 +362,7 @@ void Sequence::UniformizeMessageID() {
     for (auto& message : messages) {
       if (message.id != -1) {
         if (used.count(message.id)) {
-          std::cout << "Found two messages with the same id: " << message.id
+          std::cerr << "Found two messages with the same id: " << message.id
                     << std::endl;
           message.id = -1;
         } else {
@@ -385,10 +386,10 @@ void Sequence::UniformizeMessageID() {
         for (int id : {dependency.from, dependency.to}) {
           auto it = message_index.find(id);
           if (it == message_index.end()) {
-            std::wcout << "* Ignored dependency: \"" << actor.name << ": "
+            std::wcerr << "* Ignored dependency: \"" << actor.name << ": "
                        << dependency.from << " < " << dependency.to << "\"."
                        << std::endl;
-            std::wcout << "  It cannot be used because the message ID \"" << id
+            std::wcerr << "  It cannot be used because the message ID \"" << id
                        << "\" doesn't exist" << std::endl;
             return true;
           }
@@ -396,10 +397,10 @@ void Sequence::UniformizeMessageID() {
           const Message& message = messages[it->second];
           if (actor.name != message.from &&  //
               actor.name != message.to) {
-            std::wcout << "* Ignored dependency: \"" << actor.name << ": "
+            std::wcerr << "* Ignored dependency: \"" << actor.name << ": "
                        << dependency.from << " < " << dependency.to << "\"."
                        << std::endl;
-            std::wcout << "  It cannot be used because the message \""
+            std::wcerr << "  It cannot be used because the message \""
                        << message.from << " -> " << message.to << ": "
                        << message.messages[0]
                        << "\" has nothing to do with actor " << actor.name
@@ -464,6 +465,14 @@ void Sequence::AddMessageCommand(
   message.from = GetText(message_command->text(0));
   message.to = GetText(message_command->text(1));
 
+  if (message.from == message.to) {
+    std::cerr << "Self messages are not supported yet. It has been ignored."
+              << std::endl;
+    std::cerr << "See https://github.com/ArthurSonzogni/Diagon/issues/63"
+              << std::endl;
+    return;
+  }
+
   if (message_command->arrow()->ARROW_LEFT()) {
     std::swap(message.from, message.to);
   }
@@ -553,7 +562,7 @@ void Sequence::LayoutComputeActorsPositions() {
       }
     }
     if (i++ > 500) {
-      std::cout << "Something went wrong!" << std::endl;
+      std::cerr << "Something went wrong!" << std::endl;
       break;
     }
   }
diff --git a/src/translator/sequence/Sequence.hpp b/src/translator/sequence/Sequence.hpp
index 2cd789b..ff5a364 100644
--- a/src/translator/sequence/Sequence.hpp
+++ b/src/translator/sequence/Sequence.hpp
@@ -95,11 +95,13 @@ class Sequence : public Translator {
   int GetNumber(SequenceParser::NumberContext* number);
   std::wstring GetText(SequenceParser::TextContext* text);
 
+  // 1.1) Check input validity.
+  bool ContainsSelfMessage();
+
   // 2) Clean the representation.
   void UniformizeInternalRepresentation();
   void UniformizeActors();
   void UniformizeMessageID();
-
   void SplitByBackslashN();
 
   // 3) Layout.
diff --git a/test/Sequence/cve-2023-27390/input b/test/Sequence/cve-2023-27390/input
new file mode 100644
index 0000000..0def277
--- /dev/null
+++ b/test/Sequence/cve-2023-27390/input
@@ -0,0 +1 @@
+A->A:POC_BOF
diff --git a/test/Sequence/cve-2023-27390/output b/test/Sequence/cve-2023-27390/output
new file mode 100644
index 0000000..e69de29