--- core/fpdfapi/page/cpdf_form.h
+++ core/fpdfapi/page/cpdf_form.h
@@ -28,7 +28,22 @@
     RecursionState();
     ~RecursionState();
 
+    // returns false if that form is already getting parsed
+    bool PushForm(CPDF_Stream* pForm)
+    {
+      if (std::find(current_forms.begin(), current_forms.end(), pForm) != current_forms.end())
+        return false;
+      current_forms.push_back(pForm);
+      return true;
+    }
+
+    void PopForm()
+    {
+      current_forms.pop_back();
+    }
+
     std::set<const uint8_t*> parsed_set;
+    std::vector<CPDF_Stream*> current_forms;
   };
 
   // Helper method to choose the first non-null resources dictionary.
--- core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -754,7 +754,10 @@
 
   const ByteString type = pXObject->GetDict()->GetByteStringFor("Subtype");
   if (type == "Form") {
+    if (!recursion_state_->PushForm(pXObject.Get()))
+        return;
     AddForm(std::move(pXObject), name);
+    recursion_state_->PopForm();
     return;
   }