diff --git a/src/txmempool.h b/src/txmempool.h
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -278,13 +278,16 @@
 
 /** \class CompareTxMemPoolEntryByScore
  *
- *  Sort by score of entry ((fee+delta)/size) in descending order
+ *  Sort by feerate of entry (fee/size) in descending order
+ *  This is only used for transaction relay, so we use GetFee()
+ *  instead of GetModifiedFee() to avoid leaking prioritization
+ *  information via the sort order.
  */
 class CompareTxMemPoolEntryByScore {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) const {
-        double f1 = b.GetTxSize() * (a.GetModifiedFee() / SATOSHI);
-        double f2 = a.GetTxSize() * (b.GetModifiedFee() / SATOSHI);
+        double f1 = b.GetTxSize() * (a.GetFee() / SATOSHI);
+        double f2 = a.GetTxSize() * (b.GetFee() / SATOSHI);
         if (f1 == f2) {
             return b.GetTx().GetId() < a.GetTx().GetId();
         }
@@ -415,8 +418,11 @@
  *
  * mapTx is a boost::multi_index that sorts the mempool on 4 criteria:
  * - transaction hash
- * - feerate [we use max(feerate of tx, feerate of tx with all descendants)]
+ * - descendant feerate [we use max(feerate of tx, feerate of tx with all
+ * descendants)]
  * - time in mempool
+ * - ancestor feerate [we use min(feerate of tx, feerate of tx with all
+ * unconfirmed ancestors)]
  *
  * Note: the term "descendant" refers to in-mempool transactions that depend on
  * this one, while "ancestor" refers to in-mempool transactions that a given