diff --git a/docs/changelog/109006.yaml b/docs/changelog/109006.yaml
new file mode 100644
index 0000000000000..57a514977e85d
--- /dev/null
+++ b/docs/changelog/109006.yaml
@@ -0,0 +1,5 @@
+pr: 109006
+summary: Upgrade hppc to 0.9.1
+area: Infra/Core
+type: upgrade
+issues: []
diff --git a/gradle/verification-metadata.xml b/gradle/verification-metadata.xml
index 41c3bafde5e33..95fa6c99d851b 100644
--- a/gradle/verification-metadata.xml
+++ b/gradle/verification-metadata.xml
@@ -149,9 +149,9 @@
             <sha256 value="05f81d4b911d311ee7ac4849ebf78b303e07743418d4e89a5595422bf3802314" origin="Generated by Gradle"/>
          </artifact>
       </component>
-      <component group="com.carrotsearch" name="hppc" version="0.8.1">
-         <artifact name="hppc-0.8.1.jar">
-            <sha256 value="f540703478636d88f699f4666242e6fc9175a996c08ddceaf02106517b970406" origin="Generated by Gradle"/>
+      <component group="com.carrotsearch" name="hppc" version="0.9.1">
+         <artifact name="hppc-0.9.1.jar">
+            <sha256 value="d58706a2be60c972452550cdba79870bf481447c50eb718308e33a6ba45c65ec" origin="Generated by Gradle"/>
          </artifact>
       </component>
       <component group="com.carrotsearch.randomizedtesting" name="randomizedtesting-runner" version="2.8.0">
diff --git a/server/build.gradle b/server/build.gradle
index 03713bc3d2837..1f926a95bef3c 100644
--- a/server/build.gradle
+++ b/server/build.gradle
@@ -59,7 +59,7 @@ dependencies {
 
   // utilities
   api project(":libs:elasticsearch-cli")
-  implementation 'com.carrotsearch:hppc:0.8.1'
+  implementation 'com.carrotsearch:hppc:0.9.1'
 
   // precentil ranks aggregation
   api 'org.hdrhistogram:HdrHistogram:2.1.9'
diff --git a/server/src/main/java/module-info.java b/server/src/main/java/module-info.java
index d8682500c49d6..c56aa6889e33a 100644
--- a/server/src/main/java/module-info.java
+++ b/server/src/main/java/module-info.java
@@ -35,7 +35,7 @@
     requires org.elasticsearch.vec;
 
     requires com.sun.jna;
-    requires hppc;
+    requires com.carrotsearch.hppc;
     requires HdrHistogram;
     requires jopt.simple;
     requires log4j2.ecs.layout;
diff --git a/server/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java b/server/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java
index cf8e0608ecbd4..11a95641e5ed8 100644
--- a/server/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java
+++ b/server/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java
@@ -1121,6 +1121,10 @@ public ShardRouting[] drain() {
             return mutableShardRoutings;
         }
 
+        static <T> boolean equalListsWithoutOrder(List<T> a, List<T> b) {
+            return a.size() == b.size() && new HashSet<>(a).containsAll(b);
+        }
+
         @Override
         public boolean equals(Object o) {
             if (this == o) {
@@ -1132,8 +1136,8 @@ public boolean equals(Object o) {
             UnassignedShards that = (UnassignedShards) o;
             return primaries == that.primaries
                 && ignoredPrimaries == that.ignoredPrimaries
-                && unassigned.equals(that.unassigned)
-                && ignored.equals(that.ignored);
+                && equalListsWithoutOrder(unassigned, that.unassigned)
+                && equalListsWithoutOrder(ignored, that.ignored);
         }
 
         @Override