diff --git a/src/network/access/qhttp2protocolhandler.cpp b/src/network/access/qhttp2protocolhandler.cpp
index 88963f89687..707ef8de54e 100644
--- a/src/network/access/qhttp2protocolhandler.cpp
+++ b/src/network/access/qhttp2protocolhandler.cpp
@@ -10,10 +10,12 @@
 #include <private/qnoncontiguousbytedevice_p.h>
 
 #include <QtNetwork/qabstractsocket.h>
+
 #include <QtCore/qloggingcategory.h>
 #include <QtCore/qendian.h>
 #include <QtCore/qdebug.h>
 #include <QtCore/qlist.h>
+#include <QtCore/qnumeric.h>
 #include <QtCore/qurl.h>
 
 #include <qhttp2configuration.h>
@@ -90,8 +92,10 @@ std::vector<uchar> assemble_hpack_block(const std::vector<Http2::Frame> &frames)
     std::vector<uchar> hpackBlock;
 
     quint32 total = 0;
-    for (const auto &frame : frames)
-        total += frame.hpackBlockSize();
+    for (const auto &frame : frames) {
+        if (qAddOverflow(total, frame.hpackBlockSize(), &total))
+            return hpackBlock;
+    }
 
     if (!total)
         return hpackBlock;