diff --git a/src/gui/painting/qmath_p.h b/src/gui/painting/qmath_p.h
index d4e5be8339b..d4a74af5c56 100644
--- a/src/gui/painting/qmath_p.h
+++ b/src/gui/painting/qmath_p.h
@@ -34,6 +34,10 @@ inline QRect qt_mapFillRect(const QRectF &rect, const QTransform &xf)
     // as that can sometimes be slightly off around the .5 point, leading to wrong rounding
     QPoint pt1 = xf.map(rect.topLeft()).toPoint();
     QPoint pt2 = xf.map(rect.bottomRight()).toPoint();
+    // cut short if the result will be an empty QRect anyway
+    // side effect: avoids overflows in the calculations below
+    if (Q_UNLIKELY(pt1.x() == pt2.x() || pt1.y() == pt2.y()))
+        return QRect();
     // Normalize and adjust for the QRect vs. QRectF bottomright
     return QRect::span(pt1, pt2).adjusted(0, 0, -1, -1);
 }
diff --git a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
index 9ef5c6f34e1..575b4bb70a0 100644
--- a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
+++ b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
@@ -1741,6 +1741,25 @@ void tst_QPainter::setClipRect()
         p.setClipRect(QRectF(10.5, 10.5, 10.5, -10.5));
         QVERIFY(p.clipRegion().isEmpty());
     }
+
+    // extreme transform, values reverse-engineered from oss-fuzz issue 406541912
+    // crashed with a failed assert due to an integer overflow
+    {
+        QPainter p(&img);
+        p.setTransform(QTransform(37.7, 0., 0.,
+                                  0., 233., 0.,
+                                  18.85, -163099999883.5, 1.));
+        p.setClipRect(QRect(0, 0, 10, 1), Qt::ReplaceClip);
+    }
+
+    // the same extreme transform, edited to overflow on the x-axis instead
+    {
+        QPainter p(&img);
+        p.setTransform(QTransform(233., 0., 0.,
+                                  0., 37.7, 0.,
+                                  -163099999883.5, 18.85, 1.));
+        p.setClipRect(QRect(0, 0, 1, 10), Qt::ReplaceClip);
+    }
 }
 
 /*