diff --git a/extensions/undertow/runtime/src/main/java/io/quarkus/undertow/runtime/KnownPathResourceManager.java b/extensions/undertow/runtime/src/main/java/io/quarkus/undertow/runtime/KnownPathResourceManager.java
index d2d68e83c387a..bac53c8446fea 100644
--- a/extensions/undertow/runtime/src/main/java/io/quarkus/undertow/runtime/KnownPathResourceManager.java
+++ b/extensions/undertow/runtime/src/main/java/io/quarkus/undertow/runtime/KnownPathResourceManager.java
@@ -81,7 +81,11 @@ private class DirectoryResource implements Resource {
         private final String path;
 
         private DirectoryResource(String path) {
-            this.path = path.replaceAll("\\\\", "/");
+            this.path = evaluatePath(path);
+        }
+
+        private String evaluatePath(String path) {
+            return IS_WINDOWS ? path.replaceAll("\\\\", "/") : path;
         }
 
         @Override
@@ -134,9 +138,7 @@ public List<Resource> list() {
                         continue;
                     }
                     if (i.startsWith(slashPath)) {
-                        if (IS_WINDOWS) {
-                            i = i.replaceAll("\\\\", "/"); // correct Windows paths
-                        }
+                        i = evaluatePath(i);
                         if (!i.substring(slashPath.length()).contains("/")) {
                             try {
                                 Resource resource = underlying.getResource(i);