2 files changed, 23 insertions, 0 deletions
diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h
index 756850932e..e1901ebdce 100644
--- a/core/include/fpdfapi/fpdf_parser.h
+++ b/core/include/fpdfapi/fpdf_parser.h
@@ -9,6 +9,7 @@
 
 #include <map>
 #include <memory>
+#include <set>
 
 #include "core/include/fpdfapi/fpdf_objects.h"
 #include "core/include/fxcrt/fx_system.h"
@@ -536,6 +537,9 @@ class CPDF_Parser {
   // streams in |m_ObjectStreamMap| are valid.
   std::map<CPDF_StreamAcc*, StreamObjectCache> m_ObjCache;
 
+  // All indirect object numbers that are being parsed.
+  std::set<FX_DWORD> m_ParsingObjNums;
+
   friend class CPDF_Creator;
   friend class CPDF_DataAvail;
 };
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index ad97d1f369..236ecaa837 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -36,6 +36,20 @@ struct SearchTagRecord {
   FX_DWORD m_Offset;
 };
 
+template <typename T>
+class ScopedSetInsertion {
+ public:
+  ScopedSetInsertion(std::set<T>* org_set, T elem)
+      : m_Set(org_set), m_Entry(elem) {
+    m_Set->insert(m_Entry);
+  }
+  ~ScopedSetInsertion() { m_Set->erase(m_Entry); }
+
+ private:
+  std::set<T>* const m_Set;
+  const T m_Entry;
+};
+
 int CompareFileSize(const void* p1, const void* p2) {
   return *(FX_FILESIZE*)p1 - *(FX_FILESIZE*)p2;
 }
@@ -1193,6 +1207,11 @@ CPDF_Object* CPDF_Parser::ParseIndirectObject(CPDF_IndirectObjects* pObjList,
   if (!IsValidObjectNumber(objnum))
     return nullptr;
 
+  // Prevent circular parsing the same object.
+  if (pdfium::ContainsKey(m_ParsingObjNums, objnum))
+    return nullptr;
+  ScopedSetInsertion<FX_DWORD> local_insert(&m_ParsingObjNums, objnum);
+
   if (m_V5Type[objnum] == 1 || m_V5Type[objnum] == 255) {
     FX_FILESIZE pos = m_ObjectInfo[objnum].pos;
     if (pos <= 0)