1 files changed, 11 insertions, 2 deletions
diff --git a/core/fpdfapi/parser/cpdf_data_avail.cpp b/core/fpdfapi/parser/cpdf_data_avail.cpp
index 38e857f22f..91fc8c1087 100644
--- a/core/fpdfapi/parser/cpdf_data_avail.cpp
+++ b/core/fpdfapi/parser/cpdf_data_avail.cpp
@@ -1171,13 +1171,22 @@ CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::CheckLinearizedData() {
     return DataError;
 
   if (!m_bMainXRefLoadTried) {
+    ASSERT(m_pDocument->GetParser()->GetTrailer());
+    const FX_SAFE_FILESIZE main_xref_offset =
+        m_pDocument->GetParser()->GetTrailer()->GetIntegerFor("Prev");
+    if (!main_xref_offset.IsValid())
+      return DataError;
+
+    if (main_xref_offset.ValueOrDie() == 0)
+      return DataAvailable;
+
     FX_SAFE_SIZE_T data_size = m_dwFileLen;
-    data_size -= m_pLinearized->GetLastXRefOffset();
+    data_size -= main_xref_offset.ValueOrDie();
     if (!data_size.IsValid())
       return DataError;
 
     if (!GetValidator()->CheckDataRangeAndRequestIfUnavailable(
-            m_pLinearized->GetLastXRefOffset(), data_size.ValueOrDie()))
+            main_xref_offset.ValueOrDie(), data_size.ValueOrDie()))
       return DataNotAvailable;
 
     CPDF_Parser::Error eRet =