1 files changed, 4 insertions, 0 deletions
diff --git a/src/corelib/tools/qbitarray.cpp b/src/corelib/tools/qbitarray.cpp
index 8c750dd01cb..20fb7f53044 100644
--- a/src/corelib/tools/qbitarray.cpp
+++ b/src/corelib/tools/qbitarray.cpp
@@ -900,6 +900,10 @@ QDataStream &operator<<(QDataStream &out, const QBitArray &ba)
 {
     const qsizetype len = ba.size();
     if (out.version() < QDataStream::Qt_6_0) {
+        if (Q_UNLIKELY(len > qsizetype{(std::numeric_limits<qint32>::max)()})) {
+            out.setStatus(QDataStream::WriteFailed); // ### SizeLimitExceeded
+            return out;
+        }
         out << quint32(len);
     } else {
         out << quint64(len);