diff --git a/src/corelib/mimetypes/qmimemagicrule.cpp b/src/corelib/mimetypes/qmimemagicrule.cpp
index 7a807dccdb..5bbf1bba9d 100644
--- a/src/corelib/mimetypes/qmimemagicrule.cpp
+++ b/src/corelib/mimetypes/qmimemagicrule.cpp
@@ -299,20 +299,30 @@ QMimeMagicRule::QMimeMagicRule(const QString &type,
         }
         break;
     case Big16:
-    case Host16:
     case Little16:
         if (m_number <= quint16(-1)) {
             m_number = m_type == Little16 ? qFromLittleEndian<quint16>(m_number) : qFromBigEndian<quint16>(m_number);
+            if (m_numberMask != 0)
+                m_numberMask = m_type == Little16 ? qFromLittleEndian<quint16>(m_numberMask) : qFromBigEndian<quint16>(m_numberMask);
+        }
+        Q_FALLTHROUGH();
+    case Host16:
+        if (m_number <= quint16(-1)) {
             if (m_numberMask == 0)
                 m_numberMask = quint16(-1);
             m_matchFunction = &QMimeMagicRule::matchNumber<quint16>;
         }
         break;
     case Big32:
-    case Host32:
     case Little32:
         if (m_number <= quint32(-1)) {
             m_number = m_type == Little32 ? qFromLittleEndian<quint32>(m_number) : qFromBigEndian<quint32>(m_number);
+            if (m_numberMask != 0)
+                m_numberMask = m_type == Little32 ? qFromLittleEndian<quint32>(m_numberMask) : qFromBigEndian<quint32>(m_numberMask);
+        }
+        Q_FALLTHROUGH();
+    case Host32:
+        if (m_number <= quint32(-1)) {
             if (m_numberMask == 0)
                 m_numberMask = quint32(-1);
             m_matchFunction = &QMimeMagicRule::matchNumber<quint32>;