diff --git a/api-sheriff/src/main/java/de/cuioss/sheriff/gateway/config/load/ConfigLoader.java b/api-sheriff/src/main/java/de/cuioss/sheriff/gateway/config/load/ConfigLoader.java
index aba44bc..496ec5d 100644
--- a/api-sheriff/src/main/java/de/cuioss/sheriff/gateway/config/load/ConfigLoader.java
+++ b/api-sheriff/src/main/java/de/cuioss/sheriff/gateway/config/load/ConfigLoader.java
@@ -26,7 +26,6 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
-import java.util.Set;
 import java.util.function.Consumer;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
@@ -55,10 +54,11 @@
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
 import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
-import com.networknt.schema.JsonSchema;
-import com.networknt.schema.JsonSchemaFactory;
-import com.networknt.schema.SpecVersion;
-import com.networknt.schema.ValidationMessage;
+import com.networknt.schema.Error;
+import com.networknt.schema.InputFormat;
+import com.networknt.schema.Schema;
+import com.networknt.schema.SchemaRegistry;
+import com.networknt.schema.SpecificationVersion;
 import org.jspecify.annotations.Nullable;
 import org.yaml.snakeyaml.LoaderOptions;
 import org.yaml.snakeyaml.Yaml;
@@ -110,8 +110,8 @@ public final class ConfigLoader {
     private final Path configDir;
     private final EnvSecretResolver secretResolver;
     private final ObjectMapper mapper;
-    private final JsonSchema gatewaySchema;
-    private final JsonSchema endpointSchema;
+    private final Schema gatewaySchema;
+    private final Schema endpointSchema;
 
     /**
      * Creates a loader for the given configuration directory.
@@ -125,9 +125,9 @@ public ConfigLoader(Path configDir, EnvSecretResolver secretResolver) {
         this.configDir = Objects.requireNonNull(configDir, "configDir");
         this.secretResolver = Objects.requireNonNull(secretResolver, "secretResolver");
         this.mapper = buildMapper();
-        JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V202012);
-        this.gatewaySchema = loadSchema(factory, "/schema/gateway.schema.json");
-        this.endpointSchema = loadSchema(factory, "/schema/endpoint.schema.json");
+        SchemaRegistry registry = SchemaRegistry.withDefaultDialect(SpecificationVersion.DRAFT_2020_12);
+        this.gatewaySchema = loadSchema(registry, "/schema/gateway.schema.json");
+        this.endpointSchema = loadSchema(registry, "/schema/endpoint.schema.json");
     }
 
     /**
@@ -316,9 +316,12 @@ private static boolean withinExpansionLimits(Path path, String file, List<Config
         }
     }
 
-    private static void validate(JsonSchema schema, JsonNode node, String file, List<ConfigError> errors) {
-        Set<ValidationMessage> messages = schema.validate(node);
-        for (ValidationMessage message : messages) {
+    private static void validate(Schema schema, JsonNode node, String file, List<ConfigError> errors) {
+        // json-schema-validator 3.x exposes its node API on Jackson 3 (tools.jackson); this loader is
+        // built on Jackson 2 (com.fasterxml.jackson). Bridge the already-parsed Jackson 2 tree through its
+        // own JSON rendering (JsonNode.toString() is total — no checked exception) so the validator
+        // re-parses it with its own mapper; Jackson 3 never enters this code.
+        for (Error message : schema.validate(node.toString(), InputFormat.JSON)) {
             errors.add(new ConfigError(file, message.getInstanceLocation().toString(), message.getMessage()));
         }
     }
@@ -464,12 +467,12 @@ private static YAMLFactory hardenedYamlFactory() {
                 .build();
     }
 
-    private static JsonSchema loadSchema(JsonSchemaFactory factory, String resource) {
+    private static Schema loadSchema(SchemaRegistry registry, String resource) {
         try (InputStream stream = ConfigLoader.class.getResourceAsStream(resource)) {
             if (stream == null) {
                 throw new IllegalStateException("Missing bundled schema resource: " + resource);
             }
-            return factory.getSchema(stream);
+            return registry.getSchema(stream);
         } catch (IOException e) {
             throw new IllegalStateException("Cannot read bundled schema resource: " + resource, e);
         }
diff --git a/pom.xml b/pom.xml
index cd4850c..7d5f9aa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -52,7 +52,7 @@
              its JUnit Jupiter version to whatever the Quarkus BOM ships. -->
         <version.quarkus>3.37.3</version.quarkus>
         <version.token-sheriff>0.9.2</version.token-sheriff>
-        <version.json-schema-validator>1.5.9</version.json-schema-validator>
+        <version.json-schema-validator>3.0.6</version.json-schema-validator>
         <!-- Default empty argLine for JaCoCo compatibility - JaCoCo will override this when active -->
         <argLine />
     </properties>