diff --git a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceGenerateChallengeClient.java b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceGenerateChallengeClient.java
index d76036bf432de..7cdeebb87fece 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceGenerateChallengeClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceGenerateChallengeClient.java
@@ -52,7 +52,13 @@ public class FaceGenerateChallengeClient extends GenerateChallengeClient<ISessio
 
     void onChallengeGenerated(int sensorId, int userId, long challenge) {
         try {
-            getListener().onChallengeGenerated(sensorId, userId, challenge);
+            final ClientMonitorCallbackConverter listener = getListener();
+            if (listener == null) {
+                Slog.e(TAG, "Listener is null in onChallengeGenerated");
+                mCallback.onClientFinished(this, false /* success */);
+                return;
+            }
+            listener.onChallengeGenerated(sensorId, userId, challenge);
             mCallback.onClientFinished(this, true /* success */);
         } catch (RemoteException e) {
             Slog.e(TAG, "Unable to send challenge", e);
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintGenerateChallengeClient.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintGenerateChallengeClient.java
index 6d0148190a602..4f54f8ade7c00 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintGenerateChallengeClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintGenerateChallengeClient.java
@@ -53,7 +53,13 @@ class FingerprintGenerateChallengeClient extends GenerateChallengeClient<ISessio
 
     void onChallengeGenerated(int sensorId, int userId, long challenge) {
         try {
-            getListener().onChallengeGenerated(sensorId, userId, challenge);
+            final ClientMonitorCallbackConverter listener = getListener();
+            if (listener == null) {
+                Slog.e(TAG, "Listener is null in onChallengeGenerated");
+                mCallback.onClientFinished(this, false /* success */);
+                return;
+            }
+            listener.onChallengeGenerated(sensorId, userId, challenge);
             mCallback.onClientFinished(this, true /* success */);
         } catch (RemoteException e) {
             Slog.e(TAG, "Unable to send challenge", e);