diff --git a/pom.xml b/pom.xml
index 58a360914..73e801a67 100644
--- a/pom.xml
+++ b/pom.xml
@@ -37,7 +37,7 @@
         <version.jakarta.servlet>6.0.0</version.jakarta.servlet>
         <version.jakarta.websocket>2.0.0</version.jakarta.websocket>
         <version.graphql-java-federation>2.1.1</version.graphql-java-federation>
-        <version.graphql-java>20.2</version.graphql-java>
+        <version.graphql-java>21.1</version.graphql-java>
         <verison.io.micrometer>1.11.3</verison.io.micrometer>
         <version.vertx>4.4.1</version.vertx>
         <version.smallrye-opentelemetry>2.4.0</version.smallrye-opentelemetry>
diff --git a/server/implementation/src/main/java/io/smallrye/graphql/execution/datafetcher/helper/ErrorResultHelper.java b/server/implementation/src/main/java/io/smallrye/graphql/execution/datafetcher/helper/ErrorResultHelper.java
index b6bb32ce8..05dd304c6 100644
--- a/server/implementation/src/main/java/io/smallrye/graphql/execution/datafetcher/helper/ErrorResultHelper.java
+++ b/server/implementation/src/main/java/io/smallrye/graphql/execution/datafetcher/helper/ErrorResultHelper.java
@@ -51,7 +51,14 @@ public List<GraphQLError> toGraphQLErrors(DataFetchingEnvironment dfe, Throwable
                 .exception(t)
                 .build();
 
-        DataFetcherExceptionHandlerResult exceptionHandlerResult = exceptionHandler.onException(handlerParameters);
+        DataFetcherExceptionHandlerResult exceptionHandlerResult = null;
+        try {
+            exceptionHandlerResult = exceptionHandler.handleException(handlerParameters).get();
+        } catch (Exception e) {
+            // this should generally not happen - exceptionHandler.handleException doesn't do any IO and doesn't
+            // throw exceptions, so maybe only if we get interrupted at the right moment
+            throw new RuntimeException(e);
+        }
 
         return exceptionHandlerResult.getErrors();
     }
diff --git a/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExceptionHandler.java b/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExceptionHandler.java
index 2e2e9ae18..85186dfc2 100644
--- a/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExceptionHandler.java
+++ b/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExceptionHandler.java
@@ -2,6 +2,8 @@
 
 import static io.smallrye.graphql.SmallRyeGraphQLServerLogging.log;
 
+import java.util.concurrent.CompletableFuture;
+
 import graphql.ExceptionWhileDataFetching;
 import graphql.execution.DataFetcherExceptionHandler;
 import graphql.execution.DataFetcherExceptionHandlerParameters;
@@ -20,7 +22,8 @@ public class ExceptionHandler implements DataFetcherExceptionHandler {
     private final Config config = Config.get();
 
     @Override
-    public DataFetcherExceptionHandlerResult onException(DataFetcherExceptionHandlerParameters handlerParameters) {
+    public CompletableFuture<DataFetcherExceptionHandlerResult> handleException(
+            DataFetcherExceptionHandlerParameters handlerParameters) {
         Throwable throwable = handlerParameters.getException();
         throwable = unwrapThrowable(throwable);
         SourceLocation sourceLocation = handlerParameters.getSourceLocation();
@@ -30,7 +33,8 @@ public DataFetcherExceptionHandlerResult onException(DataFetcherExceptionHandler
             log.dataFetchingError(throwable);
         }
 
-        return DataFetcherExceptionHandlerResult.newResult().error(error).build();
+        // we don't do any IO in this method, so we can just synchronously compute the result and return after that
+        return CompletableFuture.completedFuture(DataFetcherExceptionHandlerResult.newResult().error(error).build());
     }
 
     private ExceptionWhileDataFetching getExceptionWhileDataFetching(Throwable throwable, SourceLocation sourceLocation,