diff --git a/jetty-ee10/jetty-ee10-servlets/src/main/java/org/eclipse/jetty/ee10/servlets/DoSFilter.java b/jetty-ee10/jetty-ee10-servlets/src/main/java/org/eclipse/jetty/ee10/servlets/DoSFilter.java
index d2c7fb4f7c23..0ba612d7b63d 100644
--- a/jetty-ee10/jetty-ee10-servlets/src/main/java/org/eclipse/jetty/ee10/servlets/DoSFilter.java
+++ b/jetty-ee10/jetty-ee10-servlets/src/main/java/org/eclipse/jetty/ee10/servlets/DoSFilter.java
@@ -124,7 +124,7 @@ public class DoSFilter implements Filter
     private static final Pattern IPv4_PATTERN = Pattern.compile(IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP);
     private static final String IPv6_GROUP = "(\\p{XDigit}{1,4})";
     private static final Pattern IPv6_PATTERN = Pattern.compile(IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP);
-    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)");
+    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)", Pattern.CASE_INSENSITIVE);
 
     private static final String __TRACKER = "DoSFilter.Tracker";
     private static final String __THROTTLED = "DoSFilter.Throttled";
diff --git a/jetty-ee11/jetty-ee11-servlets/src/main/java/org/eclipse/jetty/ee11/servlets/DoSFilter.java b/jetty-ee11/jetty-ee11-servlets/src/main/java/org/eclipse/jetty/ee11/servlets/DoSFilter.java
index eb82c1364430..c83a0640b1bd 100644
--- a/jetty-ee11/jetty-ee11-servlets/src/main/java/org/eclipse/jetty/ee11/servlets/DoSFilter.java
+++ b/jetty-ee11/jetty-ee11-servlets/src/main/java/org/eclipse/jetty/ee11/servlets/DoSFilter.java
@@ -124,7 +124,7 @@ public class DoSFilter implements Filter
     private static final Pattern IPv4_PATTERN = Pattern.compile(IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP);
     private static final String IPv6_GROUP = "(\\p{XDigit}{1,4})";
     private static final Pattern IPv6_PATTERN = Pattern.compile(IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP);
-    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)");
+    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)", Pattern.CASE_INSENSITIVE);
 
     private static final String __TRACKER = "DoSFilter.Tracker";
     private static final String __THROTTLED = "DoSFilter.Throttled";
diff --git a/jetty-ee9/jetty-ee9-servlets/src/main/java/org/eclipse/jetty/ee9/servlets/DoSFilter.java b/jetty-ee9/jetty-ee9-servlets/src/main/java/org/eclipse/jetty/ee9/servlets/DoSFilter.java
index 9105d55d7a57..f1c1826ae83e 100644
--- a/jetty-ee9/jetty-ee9-servlets/src/main/java/org/eclipse/jetty/ee9/servlets/DoSFilter.java
+++ b/jetty-ee9/jetty-ee9-servlets/src/main/java/org/eclipse/jetty/ee9/servlets/DoSFilter.java
@@ -123,7 +123,7 @@ public class DoSFilter implements Filter
     private static final Pattern IPv4_PATTERN = Pattern.compile(IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP + "\\." + IPv4_GROUP);
     private static final String IPv6_GROUP = "(\\p{XDigit}{1,4})";
     private static final Pattern IPv6_PATTERN = Pattern.compile(IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP + ":" + IPv6_GROUP);
-    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)");
+    private static final Pattern CIDR_PATTERN = Pattern.compile("([^/]+)/(\\d+)", Pattern.CASE_INSENSITIVE);
 
     private static final String __TRACKER = "DoSFilter.Tracker";
     private static final String __THROTTLED = "DoSFilter.Throttled";