# HG changeset patch
# User A. Wilcox <AWilcox@Wilcox-Tech.com>
# Date 1729710191 18000
#      Wed Oct 23 14:03:11 2024 -0500
# Node ID 6102585e0d752de1729135d4c7d917e751b268c5
# Parent  61f7d9c0998e2ce8008cd15b187f86dfdba21a26
Bug 1926667 - Ensure JSStructuredCloneReader::readTransferMap respects endianness r?sfink

Differential Revision: https://phabricator.services.mozilla.com/D226707

diff --git a/js/src/vm/StructuredClone.cpp b/js/src/vm/StructuredClone.cpp
--- a/js/src/vm/StructuredClone.cpp
+++ b/js/src/vm/StructuredClone.cpp
@@ -3387,7 +3387,8 @@ bool JSStructuredCloneReader::readTransf
   }
 
   headerPos.write(
-      PairToUInt64(SCTAG_TRANSFER_MAP_HEADER, SCTAG_TM_TRANSFERRING));
+      NativeEndian::swapToLittleEndian(
+          PairToUInt64(SCTAG_TRANSFER_MAP_HEADER, SCTAG_TM_TRANSFERRING)));
 
   uint64_t numTransferables;
   MOZ_ALWAYS_TRUE(in.readPair(&tag, &data));
@@ -3512,7 +3513,8 @@ bool JSStructuredCloneReader::readTransf
   MOZ_ASSERT(TransferableMapHeader(data) == SCTAG_TM_TRANSFERRING);
 #endif
   headerPos.write(
-      PairToUInt64(SCTAG_TRANSFER_MAP_HEADER, SCTAG_TM_TRANSFERRED));
+      NativeEndian::swapToLittleEndian(
+          PairToUInt64(SCTAG_TRANSFER_MAP_HEADER, SCTAG_TM_TRANSFERRED)));
 
   return true;
 }