diff --git a/kotlin/scanner.c b/kotlin/scanner.c
index 4f531eb..c1faa98 100644
--- a/kotlin/scanner.c
+++ b/kotlin/scanner.c
@@ -512,8 +512,13 @@ void tree_sitter_kotlin_external_scanner_destroy(void *payload) {
   ts_free(stack);
 }
 
+// Modified by Poolside fork to fix an UB
 unsigned tree_sitter_kotlin_external_scanner_serialize(void *payload, char *buffer) {
   Stack *stack = (Stack *)payload;
+  // Poolside: in memcpy if src is nullptr it is a UB even if size is 0
+  if (stack->size == 0) {
+    return 0;
+  }
   memcpy(buffer, stack->contents, stack->size);
   return stack->size;
 }
diff --git a/scala/scanner.c b/scala/scanner.c
index 58adb7d..c746389 100644
--- a/scala/scanner.c
+++ b/scala/scanner.c
@@ -51,7 +51,11 @@ void tree_sitter_scala_external_scanner_destroy(void *payload) {
   ts_free(scanner);
 }
 
+// Modified by Poolside fork to fix an UB
 unsigned tree_sitter_scala_external_scanner_serialize(void *payload, char *buffer) {
+  if (!payload) {
+    return 0;
+  }
   Scanner *scanner = (Scanner*)payload;
 
   if ((scanner->indents.size + 3) * sizeof(int16_t) > TREE_SITTER_SERIALIZATION_BUFFER_SIZE) {
@@ -59,15 +63,15 @@ unsigned tree_sitter_scala_external_scanner_serialize(void *payload, char *buffe
   }
 
   size_t size = 0;
-  *(int16_t *)&buffer[size] = scanner->last_indentation_size;
+  memcpy(buffer + size, &scanner->last_indentation_size, sizeof(int16_t));
   size += sizeof(int16_t);
-  *(int16_t *)&buffer[size] = scanner->last_newline_count;
+  memcpy(buffer + size, &scanner->last_newline_count, sizeof(int16_t));
   size += sizeof(int16_t);
-  *(int16_t *)&buffer[size] = scanner->last_column;
+  memcpy(buffer + size, &scanner->last_column, sizeof(int16_t));
   size += sizeof(int16_t);
 
   for (unsigned i = 0; i < scanner->indents.size; i++) {
-    *(int16_t *)&buffer[size] = scanner->indents.contents[i];
+    memcpy(buffer + size, &scanner->indents.contents[i], sizeof(int16_t));
     size += sizeof(int16_t);
   }