diff --git a/src/corelib/serialization/qcborstreamreader.cpp b/src/corelib/serialization/qcborstreamreader.cpp
index ef2ec08b884..f1bea6a1f17 100644
--- a/src/corelib/serialization/qcborstreamreader.cpp
+++ b/src/corelib/serialization/qcborstreamreader.cpp
@@ -1076,19 +1076,18 @@ bool QCborStreamReader::next(int maxRecursion)
             next(maxRecursion - 1);
         if (lastError() == QCborError::NoError)
             leaveContainer();
-    } else if (isString() || isByteArray()) {
-        auto r = _readByteArray_helper();
-        while (r.status == Ok) {
-            if (isString() && r.data.size() > MaxStringSize) {
-                d->handleError(CborErrorDataTooLarge);
-                break;
-            }
-            if (isString() && !QUtf8::isValidUtf8(r.data).isValidUtf8) {
-                d->handleError(CborErrorInvalidUtf8TextString);
-                break;
-            }
-            r = _readByteArray_helper();
-        }
+    } else if (isByteArray()) {
+        char c;
+        StringResult<qsizetype> r;
+        do {
+            r = readStringChunk(&c, 1);
+        } while (r.status == Ok);
+    } else if (isString()) {
+        // we need to use actual readString so we get UTF-8 validation
+        StringResult<QString> r;
+        do {
+            r = readString();
+        } while (r.status == Ok);
     } else {
         // fixed types
         CborError err = cbor_value_advance_fixed(&d->currentElement);
diff --git a/tests/auto/corelib/serialization/cborlargedatavalidation.cpp b/tests/auto/corelib/serialization/cborlargedatavalidation.cpp
index c5cf1dc04e1..a9a31ddf572 100644
--- a/tests/auto/corelib/serialization/cborlargedatavalidation.cpp
+++ b/tests/auto/corelib/serialization/cborlargedatavalidation.cpp
@@ -117,6 +117,7 @@ void addValidationHugeDevice(qsizetype byteArrayInvalid, qsizetype stringInvalid
     qRegisterMetaType<QSharedPointer<QIODevice>>();
     QTest::addColumn<QSharedPointer<QIODevice>>("device");
     QTest::addColumn<CborError>("expectedError");
+    QTest::addColumn<CborError>("expectedValidationError");
 
     char buf[1 + sizeof(quint64)];
     auto device = [&buf](QCborStreamReader::Type t, quint64 size) {
@@ -130,21 +131,21 @@ void addValidationHugeDevice(qsizetype byteArrayInvalid, qsizetype stringInvalid
 
     // do the exact limits
     QTest::newRow("bytearray-just-too-big")
-            << device(QCborStreamReader::ByteArray, byteArrayInvalid) << CborErrorDataTooLarge;
-
-    // TODO: Fix this to work for 64-bit. The test tries to allocate too much data and fails.
-    if (sizeof(size_t) == 4) {
-        QTest::newRow("string-just-too-big")
-                << device(QCborStreamReader::String, stringInvalid) << CborErrorDataTooLarge;
-    }
+            << device(QCborStreamReader::ByteArray, byteArrayInvalid)
+            << CborErrorDataTooLarge << CborNoError;
+    QTest::newRow("string-just-too-big")
+            << device(QCborStreamReader::String, stringInvalid)
+            << CborErrorDataTooLarge << CborErrorDataTooLarge;
 
     auto addSize = [=](const char *sizename, qint64 size) {
         if (byteArrayInvalid < size)
             QTest::addRow("bytearray-%s", sizename)
-                << device(QCborStreamReader::ByteArray, size) << CborErrorDataTooLarge;
+                << device(QCborStreamReader::ByteArray, size)
+                << CborErrorDataTooLarge << CborNoError;
         if (stringInvalid < size)
             QTest::addRow("string-%s", sizename)
-                << device(QCborStreamReader::String, size) << CborErrorDataTooLarge;
+                << device(QCborStreamReader::String, size)
+                << CborErrorDataTooLarge << CborErrorDataTooLarge;
     };
     addSize("1GB", quint64(1) << 30);
     addSize("2GB", quint64(1) << 31);
diff --git a/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp b/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
index 437d8c40ceb..f04f26b42fc 100644
--- a/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
+++ b/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
@@ -958,6 +958,7 @@ void tst_QCborStreamReader::hugeDeviceValidation()
 
     QFETCH(QSharedPointer<QIODevice>, device);
     QFETCH(CborError, expectedError);
+    QFETCH(CborError, expectedValidationError);
     QCborError error = { QCborError::Code(expectedError) };
 
     device->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
@@ -966,10 +967,15 @@ void tst_QCborStreamReader::hugeDeviceValidation()
     QVERIFY(parseOne(reader).isEmpty());
     QCOMPARE(reader.lastError(), error);
 
-    // next() should fail
     reader.reset();
-    QVERIFY(!reader.next());
-    QCOMPARE(reader.lastError(), error);
+    error = { QCborError::Code(expectedValidationError) };
+    if (error == QCborError{}) {
+        // this test actually succeeds, so don't do it to avoid large memory consumption
+    } else {
+        // next() should fail
+        QVERIFY(!reader.next());
+        QCOMPARE(reader.lastError(), error);
+    }
 }
 
 static const int Recursions = 3;