diff --git a/packages/netty/src/main/java/dev/elide/bemo/transport/NativeTlsSession.java b/packages/netty/src/main/java/dev/elide/bemo/transport/NativeTlsSession.java
index 1e3517a..b3af431 100644
--- a/packages/netty/src/main/java/dev/elide/bemo/transport/NativeTlsSession.java
+++ b/packages/netty/src/main/java/dev/elide/bemo/transport/NativeTlsSession.java
@@ -79,11 +79,21 @@ private void requestClose(io.netty.channel.ChannelPromise promise, boolean halfC
         outputOnly = false;
         releasePendingReads();
       }
-      closePromise.addListener(
-          done -> {
-            if (done.isSuccess()) promise.trySuccess();
-            else promise.tryFailure(done.cause());
-          });
+      if (closePromise.isVoid()) {
+        channel
+            .closeFuture()
+            .addListener(
+                done -> {
+                  if (done.isSuccess()) promise.trySuccess();
+                  else promise.tryFailure(done.cause());
+                });
+      } else {
+        closePromise.addListener(
+            done -> {
+              if (done.isSuccess()) promise.trySuccess();
+              else promise.tryFailure(done.cause());
+            });
+      }
       return;
     }
     outputOnly = halfClose;
diff --git a/tests/transport/java/NativeTlsDoubleCloseTest.java b/tests/transport/java/NativeTlsDoubleCloseTest.java
new file mode 100644
index 0000000..16480d9
--- /dev/null
+++ b/tests/transport/java/NativeTlsDoubleCloseTest.java
@@ -0,0 +1,116 @@
+import dev.elide.bemo.transport.*;
+import io.netty.bootstrap.*;
+import io.netty.channel.*;
+import java.net.InetSocketAddress;
+import java.nio.file.*;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Verifies that a second {@code close(promise)} issued while a void-promise TLS close is in flight
+ * completes the promise successfully rather than failing with {@code IllegalStateException("void
+ * future")}. Without the fix, {@code NativeTlsSession.requestClose} calls {@code
+ * closePromise.addListener(...)} without checking {@code isVoid()}, and {@code
+ * VoidChannelPromise.addListener} throws unconditionally.
+ */
+public final class NativeTlsDoubleCloseTest {
+
+  public static void main(String[] args) throws Exception {
+    TransportNative delegate = new BackendTransport(new FfmTransportNative(Path.of(args[0])));
+    verify(delegate, Files.readAllBytes(Path.of(args[1])), Files.readAllBytes(Path.of(args[2])));
+  }
+
+  public static void verify(TransportNative delegate, byte[] cert, byte[] key) throws Exception {
+    AtomicBoolean closeInitiated = new AtomicBoolean();
+    TransportNative api =
+        new BackendTransport(delegate) {
+          @Override
+          public boolean supportsReceiveResults() {
+            return false;
+          }
+
+          @Override
+          public int tlsStep(
+              long session, int action, long plaintext, long offset, long length, long output) {
+            if (action == 3) closeInitiated.set(true);
+            return super.tlsStep(session, action, plaintext, offset, length, output);
+          }
+
+          @Override
+          public long socketSend(
+              long workload, long driver, long socket, long buffer, long offset, long length) {
+            if (closeInitiated.get()) return Long.MAX_VALUE;
+            return super.socketSend(workload, driver, socket, buffer, offset, length);
+          }
+        };
+    EventLoopGroup group =
+        new MultiThreadIoEventLoopGroup(
+            1, NativeIoHandler.newFactory(api, 0, 128, 8 * 1024 * 1024));
+    Channel server = null;
+    NativeSocketChannel client = null;
+    java.util.concurrent.CompletableFuture<NativeSocketChannel> accepted =
+        new java.util.concurrent.CompletableFuture<>();
+    try (NativeTlsContext serverTls = NativeTlsContext.server(api, cert, key, "h2");
+        NativeTlsContext clientTls = NativeTlsContext.client(api, cert, "h2")) {
+      server =
+          new ServerBootstrap()
+              .group(group)
+              .channel(NativeServerSocketChannel.class)
+              .childHandler(
+                  new ChannelInitializer<NativeSocketChannel>() {
+                    @Override
+                    protected void initChannel(NativeSocketChannel channel) {
+                      channel.tls(serverTls, null);
+                      accepted.complete(channel);
+                    }
+                  })
+              .bind(new InetSocketAddress("127.0.0.1", 0))
+              .sync()
+              .channel();
+      client =
+          (NativeSocketChannel)
+              new Bootstrap()
+                  .group(group)
+                  .channelFactory(() -> new NativeSocketChannel().tls(clientTls, "localhost"))
+                  .handler(
+                      new ChannelInboundHandlerAdapter() {
+                        @Override
+                        public void exceptionCaught(
+                            ChannelHandlerContext context, Throwable error) {
+                          context.close();
+                        }
+                      })
+                  .connect(server.localAddress())
+                  .sync()
+                  .channel();
+      client.handshakeFuture().sync();
+      NativeSocketChannel peer = accepted.get(5, TimeUnit.SECONDS);
+      peer.handshakeFuture().sync();
+      ChannelPromise secondPromise = client.newPromise();
+      NativeSocketChannel c = client;
+      group
+          .next()
+          .execute(
+              () -> {
+                c.unsafe().close(c.voidPromise());
+                c.unsafe().close(secondPromise);
+              });
+      if (!secondPromise.await(10, TimeUnit.SECONDS))
+        throw new AssertionError("second close promise was never completed (hung)");
+      if (!secondPromise.isSuccess())
+        throw new AssertionError("second close promise failed with: " + secondPromise.cause());
+      if (secondPromise.cause() != null)
+        throw new AssertionError("second close promise has unexpected cause");
+      if (!client.closeFuture().await(10, TimeUnit.SECONDS))
+        throw new AssertionError("closeFuture did not complete (channel hung)");
+      if (!client.closeFuture().isSuccess())
+        throw new AssertionError("closeFuture did not succeed");
+      System.out.println("Native TLS double-close (void then real promise) passed");
+    } finally {
+      closeInitiated.set(false);
+      if (client != null) client.close().syncUninterruptibly();
+      if (server != null) server.close().syncUninterruptibly();
+      group.shutdownGracefully(0, 5, TimeUnit.SECONDS).syncUninterruptibly();
+    }
+  }
+}
diff --git a/tools/build.py b/tools/build.py
index 8fe4564..6856ca0 100644
--- a/tools/build.py
+++ b/tools/build.py
@@ -252,7 +252,8 @@ def test_transport(native_image=False, reports=None, agent=(), native=None, env=
   else:
     for contract in ("FfmTransportTest", "NativeByteBufTest", "NativeChannelTest", "NativeLifecycleTest",
                      "NativeTlsChannelTest", "NativeTlsNegativeTest", "NativeTlsOrderingTest",
-                     "NativeTlsClosePromiseTest", "NativeTransferTest", "NativeJfrTest",
+                     "NativeTlsClosePromiseTest", "NativeTlsDoubleCloseTest",
+                     "NativeTransferTest", "NativeJfrTest",
                      "NativeReentrantCloseTest", "NativeReceiveAllocatorTest", "NativeSslEngineTest",
                      "NativeSslInteropTest", "NativeSslPolicyTest", "NativeDirectAllocatorTest",
                      "StandaloneTransportCheck"):