diff --git a/app/code/Magento/Paypal/etc/adminhtml/system/express_checkout.xml b/app/code/Magento/Paypal/etc/adminhtml/system/express_checkout.xml
index d5287659ee7d2..1d72d3a86e4be 100644
--- a/app/code/Magento/Paypal/etc/adminhtml/system/express_checkout.xml
+++ b/app/code/Magento/Paypal/etc/adminhtml/system/express_checkout.xml
@@ -124,6 +124,7 @@
                     <depends>
                         <field id="use_proxy">1</field>
                     </depends>
+                    <validate>validate-digits validate-digits-range digits-range-0-65535</validate>
                 </field>
             </group>
             <field id="enable_express_checkout" translate="label" type="select" sortOrder="20" showInDefault="1" showInWebsite="1">
diff --git a/app/code/Magento/Paypal/etc/adminhtml/system/payflow_advanced.xml b/app/code/Magento/Paypal/etc/adminhtml/system/payflow_advanced.xml
index cba36916c3305..492d4b2ac9ce4 100644
--- a/app/code/Magento/Paypal/etc/adminhtml/system/payflow_advanced.xml
+++ b/app/code/Magento/Paypal/etc/adminhtml/system/payflow_advanced.xml
@@ -76,6 +76,7 @@
                         <field id="use_proxy">1</field>
                     </depends>
                     <attribute type="shared">1</attribute>
+                    <validate>validate-digits validate-digits-range digits-range-0-65535</validate>
                 </field>
                 <field id="payflow_advanced_info" showInDefault="1" showInWebsite="1" showInStore="1" sortOrder="100">
                     <frontend_model>Magento\Paypal\Block\Adminhtml\System\Config\Payflowlink\Advanced</frontend_model>
diff --git a/app/code/Magento/Paypal/etc/adminhtml/system/payflow_link.xml b/app/code/Magento/Paypal/etc/adminhtml/system/payflow_link.xml
index ed11e8ba18d07..2e25dd6a66124 100644
--- a/app/code/Magento/Paypal/etc/adminhtml/system/payflow_link.xml
+++ b/app/code/Magento/Paypal/etc/adminhtml/system/payflow_link.xml
@@ -77,6 +77,7 @@
                         <field id="use_proxy">1</field>
                     </depends>
                     <attribute type="shared">1</attribute>
+                    <validate>validate-digits validate-digits-range digits-range-0-65535</validate>
                 </field>
                 <field id="payflowlink_info" showInDefault="1" showInWebsite="1" showInStore="1" sortOrder="90">
                     <frontend_model>Magento\Paypal\Block\Adminhtml\System\Config\Payflowlink\Info</frontend_model>
diff --git a/app/code/Magento/Paypal/etc/adminhtml/system/paypal_payflowpro.xml b/app/code/Magento/Paypal/etc/adminhtml/system/paypal_payflowpro.xml
index e5a0319bdc1bf..91396d2a95ac2 100644
--- a/app/code/Magento/Paypal/etc/adminhtml/system/paypal_payflowpro.xml
+++ b/app/code/Magento/Paypal/etc/adminhtml/system/paypal_payflowpro.xml
@@ -72,6 +72,7 @@
                         <field id="use_proxy">1</field>
                     </depends>
                     <attribute type="shared">1</attribute>
+                    <validate>validate-digits validate-digits-range digits-range-0-65535</validate>
                 </field>
             </group>
             <field id="enable_paypal_payflow" translate="label" type="select" sortOrder="20" showInDefault="1" showInWebsite="1">