diff --git a/code/API_definitions/webrtc-call-handling.yaml b/code/API_definitions/webrtc-call-handling.yaml
index 873fa2f..3a9e6c5 100644
--- a/code/API_definitions/webrtc-call-handling.yaml
+++ b/code/API_definitions/webrtc-call-handling.yaml
@@ -451,6 +451,7 @@ components:
       schema:
         type: string
         maxLength: 256
+        pattern: '^[^\x00-\x1F\x7F]+$'
     pathParamMediaSessionId:
       name: mediaSessionId
       in: path
@@ -461,6 +462,7 @@ components:
       schema:
         type: string
         maxLength: 256
+        pattern: '^[^\x00-\x1F\x7F]+$'
     x-correlator:
       name: x-correlator
       in: header
@@ -483,6 +485,7 @@ components:
         originatorName:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: Friendly name of the call originator
           example: 'Alice'
         receiverAddress:
@@ -490,6 +493,7 @@ components:
         receiverName:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: Friendly name of the call terminator
           example: 'Bob'
         offer:
@@ -537,6 +541,7 @@ components:
             mediaSessionId:
               type: string
               maxLength: 256
+              pattern: '^[^\x00-\x1F\x7F]+$'
               description: >-
                 The media session ID created by the network.
               example: 0AEE1B58BAEEDA3EABA42B32EBB3DFE07E9CFF402EAF9EED8EF
@@ -568,6 +573,7 @@ components:
         sdp:
           type: string
           maxLength: 65536
+          pattern: '^[^\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+$'
           description: |-
             An inlined session description in SDP format [RFC4566].If XML syntax is used, the content of this element SHALL be embedded in a CDATA section
     SessionStatus:
diff --git a/code/API_definitions/webrtc-events-subscriptions.yaml b/code/API_definitions/webrtc-events-subscriptions.yaml
index 8d21cae..e93ccc4 100644
--- a/code/API_definitions/webrtc-events-subscriptions.yaml
+++ b/code/API_definitions/webrtc-events-subscriptions.yaml
@@ -706,6 +706,7 @@ components:
     RegistrationId:
       type: string
       maxLength: 256
+      pattern: '^[^\x00-\x1F\x7F]+$'
       description: The unique identifier of the WebRTC registration.
       example: ln3C-ttOSk-ObcQ7A0-tYO1LXqy
 
@@ -718,6 +719,7 @@ components:
             type:
               type: string
               maxLength: 512
+              pattern: '^[^\x00-\x1F\x7F]+$'
               description: event-type that describes type of notification
           discriminator:
             propertyName: "type"
@@ -791,6 +793,7 @@ components:
         originatorName:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: Friendly name of the call originator
           example: 'Alice'
         receiverAddress:
@@ -802,6 +805,7 @@ components:
         receiverName:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: Friendly name of the call terminator
           example: 'Bob'
         status:
@@ -833,11 +837,13 @@ components:
         mediaSessionId:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: The media session ID created by the network. The mediaSessionId shall not be included in POST requests by the client, but must be included in the notifications from the network to client.
           example: '0AEE1B58BAEEDA3EABA42B32EBB3DFE07E9CFF402EAF9EED8EF'
         reason:
           type: string
           maxLength: 2048
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: The description of the event that has happened within the session
         sequenceNumber:
           type: integer
@@ -877,6 +883,7 @@ components:
         sdp:
           type: string
           maxLength: 65536
+          pattern: '^[^\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+$'
           description: |-
             An inlined session description in SDP format [RFC4566].If XML syntax is used, the content of this element SHALL be embedded in a CDATA section
 
@@ -952,6 +959,7 @@ components:
         terminationDescription:
           type: string
           maxLength: 2048
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: Human-readable explanation of why the registration was terminated
         terminationReason:
           $ref: "#/components/schemas/RegistrationTerminationReason"
diff --git a/code/API_definitions/webrtc-registration.yaml b/code/API_definitions/webrtc-registration.yaml
index d87ae3f..7e89711 100644
--- a/code/API_definitions/webrtc-registration.yaml
+++ b/code/API_definitions/webrtc-registration.yaml
@@ -468,6 +468,7 @@ components:
       schema:
         type: string
         maxLength: 256
+        pattern: '^[^\x00-\x1F\x7F]+$'
   schemas:
     XCorrelator:
       description: Correlator string, UUID format recommended but any string matching the pattern can be used
@@ -561,6 +562,7 @@ components:
         registrationId:
           type: string
           maxLength: 256
+          pattern: '^[^\x00-\x1F\x7F]+$'
           description: The registration session ID is returned when registering a device with the network . Clients must utilize this ID to as a parameter in the call-handling and subscription APIs.
         expiresAt:
           type: string