diff --git a/CHANGES.txt b/CHANGES.txt
index 17f31338ae..eea12c7fd7 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -5,6 +5,7 @@
  * Equality check for Paxos.Electorate should not depend on collection types (CASSANDRA-19935)
  * Fix race condition in DecayingEstimatedHistogramReservoir during rescale (CASSANDRA-19365)
 Merged from 4.0:
+ * Do not attach rows and partitions to CheckForAbort when already attached (CASSANDRA-20135)
  * Allow hint delivery during schema mismatch (CASSANDRA-20188)
  * IndexOutOfBoundsException when accessing partition where the column was deleted (CASSANDRA-20108)
  * Enhance CQLSSTableWriter to notify clients on sstable production (CASSANDRA-19800)
diff --git a/src/java/org/apache/cassandra/db/ReadCommand.java b/src/java/org/apache/cassandra/db/ReadCommand.java
index 211a9a3d93..b3a09e0249 100644
--- a/src/java/org/apache/cassandra/db/ReadCommand.java
+++ b/src/java/org/apache/cassandra/db/ReadCommand.java
@@ -36,6 +36,8 @@ import org.slf4j.LoggerFactory;
 import io.netty.util.concurrent.FastThreadLocal;
 import org.apache.cassandra.config.*;
 import org.apache.cassandra.db.filter.*;
+import org.apache.cassandra.db.transform.BasePartitions;
+import org.apache.cassandra.db.transform.BaseRows;
 import org.apache.cassandra.net.MessageFlag;
 import org.apache.cassandra.net.ParamType;
 import org.apache.cassandra.net.Verb;
@@ -616,6 +618,22 @@ public abstract class ReadCommand extends AbstractReadQuery
     {
         long lastChecked = 0;
 
+        @Override
+        protected void attachTo(BasePartitions partitions)
+        {
+            Preconditions.checkArgument(this.partitions == null || this.partitions == partitions,
+                                        "Attempted to attach 2nd different BasePartitions in StoppingTransformation; this is a bug.");
+            this.partitions = partitions;
+        }
+
+        @Override
+        protected void attachTo(BaseRows rows)
+        {
+            Preconditions.checkArgument(this.rows == null || this.rows == rows,
+                                        "Attempted to attach 2nd different BaseRows in StoppingTransformation; this is a bug.");
+            this.rows = rows;
+        }
+
         protected UnfilteredRowIterator applyToPartition(UnfilteredRowIterator partition)
         {
             if (maybeAbort())
diff --git a/src/java/org/apache/cassandra/db/transform/StoppingTransformation.java b/src/java/org/apache/cassandra/db/transform/StoppingTransformation.java
index 79563e9763..691ee39bdb 100644
--- a/src/java/org/apache/cassandra/db/transform/StoppingTransformation.java
+++ b/src/java/org/apache/cassandra/db/transform/StoppingTransformation.java
@@ -26,8 +26,8 @@ import org.apache.cassandra.db.rows.BaseRowIterator;
 // A Transformation that can stop an iterator earlier than its natural exhaustion
 public abstract class StoppingTransformation<I extends BaseRowIterator<?>> extends Transformation<I>
 {
-    private BaseIterator rows;
-    private BaseIterator partitions;
+    protected BaseIterator rows;
+    protected BaseIterator partitions;
 
     /**
      * If invoked by a subclass, any partitions iterator this transformation has been applied to will terminate