diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 02f888ed06..a0f121c8c8 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -9,6 +9,9 @@
     *   Fix some audio focus inconsistencies, e.g. not reporting full or
         transient focus loss while the player is paused
         ([#1436](https://github.com/androidx/media/issues/1436)).
+    *   Fix potential `IndexOutOfBoundsException` caused by extractors reporting
+        additional tracks after the initial preparation step
+        ([#1476](https://github.com/androidx/media/issues/1476)).
 *   Transformer:
 *   Track Selection:
 *   Extractors:
diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ProgressiveMediaPeriod.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ProgressiveMediaPeriod.java
index 444d2168d0..0ee2cc1f36 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ProgressiveMediaPeriod.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ProgressiveMediaPeriod.java
@@ -31,6 +31,7 @@ import androidx.media3.common.ParserException;
 import androidx.media3.common.TrackGroup;
 import androidx.media3.common.util.Assertions;
 import androidx.media3.common.util.ConditionVariable;
+import androidx.media3.common.util.Log;
 import androidx.media3.common.util.NullableType;
 import androidx.media3.common.util.ParsableByteArray;
 import androidx.media3.common.util.Util;
@@ -53,6 +54,7 @@ import androidx.media3.exoplayer.upstream.LoadErrorHandlingPolicy.LoadErrorInfo;
 import androidx.media3.exoplayer.upstream.Loader;
 import androidx.media3.exoplayer.upstream.Loader.LoadErrorAction;
 import androidx.media3.exoplayer.upstream.Loader.Loadable;
+import androidx.media3.extractor.DummyTrackOutput;
 import androidx.media3.extractor.Extractor;
 import androidx.media3.extractor.ExtractorOutput;
 import androidx.media3.extractor.ForwardingSeekMap;
@@ -93,6 +95,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     void onSourceInfoRefreshed(long durationUs, boolean isSeekable, boolean isLive);
   }
 
+  private static final String TAG = "ProgressiveMediaPeriod";
+
   /**
    * When the source's duration is unknown, it is calculated by adding this value to the largest
    * sample timestamp seen when buffering completes.
@@ -733,6 +737,10 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
         return sampleQueues[i];
       }
     }
+    if (sampleQueuesBuilt) {
+      Log.w(TAG, "Extractor added new track (id=" + id.id + ") after finishing tracks.");
+      return new DummyTrackOutput();
+    }
     SampleQueue trackOutput =
         SampleQueue.createWithDrm(allocator, drmSessionManager, drmEventDispatcher);
     trackOutput.setUpstreamFormatChangeListener(this);