diff --git a/ReactCommon/cxxreact/JSBigString.cpp b/ReactCommon/cxxreact/JSBigString.cpp
index 0a0571466..fb6540d14 100644
--- a/ReactCommon/cxxreact/JSBigString.cpp
+++ b/ReactCommon/cxxreact/JSBigString.cpp
@@ -52,7 +52,7 @@ JSBigFileString::~JSBigFileString() {
 const char *JSBigFileString::c_str() const {
   if (!m_data) {
     m_data =
-      (const char *) mmap(0, m_size, PROT_READ, MAP_SHARED, m_fd, m_mapOff);
+      (const char *) mmap(0, m_size, PROT_READ, MAP_PRIVATE, m_fd, m_mapOff);
     CHECK(m_data != MAP_FAILED)
       << " fd: " << m_fd
       << " size: " << m_size