diff --git a/CHANGES.txt b/CHANGES.txt
index eaf53682b8..3405820d6a 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -8,6 +8,7 @@ Merged from 4.0:
  * Fix Down nodes counter in nodetool describecluster (CASSANDRA-18512)
  * Remove unnecessary shuffling of GossipDigests in Gossiper#makeRandomGossipDigest (CASSANDRA-18546)
 Merged from 3.11:
+ * Fix CAST function for float to decimal (CASSANDRA-18647)
  * Suppress CVE-2022-45688 (CASSANDRA-18643)
  * Remove unrepaired SSTables from garbage collection when only_purge_repaired_tombstones is true (CASSANDRA-14204)
  * Wait for live endpoints in gossip waiting to settle (CASSANDRA-18543)
diff --git a/src/java/org/apache/cassandra/cql3/functions/CastFcts.java b/src/java/org/apache/cassandra/cql3/functions/CastFcts.java
index 81986c804e..20d9819c77 100644
--- a/src/java/org/apache/cassandra/cql3/functions/CastFcts.java
+++ b/src/java/org/apache/cassandra/cql3/functions/CastFcts.java
@@ -122,7 +122,10 @@ public final class CastFcts
      */
     private static <I extends Number> java.util.function.Function<I, BigDecimal> getDecimalConversionFunction(AbstractType<? extends Number> inputType)
     {
-        if (inputType == FloatType.instance || inputType == DoubleType.instance)
+        if (inputType == FloatType.instance)
+            return p -> new BigDecimal(Float.toString(p.floatValue()));
+
+        if (inputType == DoubleType.instance)
             return p -> BigDecimal.valueOf(p.doubleValue());
 
         if (inputType == IntegerType.instance)
diff --git a/test/unit/org/apache/cassandra/cql3/functions/CastFctsTest.java b/test/unit/org/apache/cassandra/cql3/functions/CastFctsTest.java
index 6efbdc0438..be0aba933c 100644
--- a/test/unit/org/apache/cassandra/cql3/functions/CastFctsTest.java
+++ b/test/unit/org/apache/cassandra/cql3/functions/CastFctsTest.java
@@ -142,7 +142,7 @@ public class CastFctsTest extends CQLTester
                        BigDecimal.valueOf(2),
                        BigDecimal.valueOf(3),
                        BigDecimal.valueOf(4),
-                       BigDecimal.valueOf(5.2F),
+                       new BigDecimal("5.2"),
                        BigDecimal.valueOf(6.3),
                        BigDecimal.valueOf(6.3),
                        BigDecimal.valueOf(4),