diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index 9aed910..30a6f03 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -480,6 +480,8 @@
 
     private static final int MODEM_ACTIVITY_TIME_OFFSET_CORRECTION_MS = 50;
 
+    private static final int LINE1_NUMBER_MAX_LEN = 50;
+
     /**
      * With support for MEP(multiple enabled profile) in Android T, a SIM card can have more than
      * one ICCID active at the same time.
@@ -7827,6 +7829,10 @@
             if (phone == null) {
                 return false;
             }
+            if (!TextUtils.isEmpty(number) && number.length() > LINE1_NUMBER_MAX_LEN) {
+                Rlog.e(LOG_TAG, "Number is too long");
+                return false;
+            }
             final String subscriberId = phone.getSubscriberId();
 
             if (DBG_MERGE) {