diff --git a/packages/plugins/sandbox-providers/kubernetes/src/pod-exec.ts b/packages/plugins/sandbox-providers/kubernetes/src/pod-exec.ts
index 91010d8a..41904008 100644
--- a/packages/plugins/sandbox-providers/kubernetes/src/pod-exec.ts
+++ b/packages/plugins/sandbox-providers/kubernetes/src/pod-exec.ts
@@ -155,7 +155,15 @@ export async function execInPod(
       websocketPromise
         .then((webSocket) => {
           ws = webSocket as WebSocketLike;
-          if (!settled && stdinStream && stdinPayload) {
+          if (settled) {
+            try {
+              ws.close();
+            } catch {
+              // Ignore best-effort close failures.
+            }
+            return;
+          }
+          if (stdinStream && stdinPayload) {
             stdinStream.end(stdinPayload);
           }
           ws.on("close", (code: number, reason: Buffer) => {
diff --git a/packages/plugins/sandbox-providers/kubernetes/test/unit/pod-exec.test.ts b/packages/plugins/sandbox-providers/kubernetes/test/unit/pod-exec.test.ts
index d3184f64..d9fb3c68 100644
--- a/packages/plugins/sandbox-providers/kubernetes/test/unit/pod-exec.test.ts
+++ b/packages/plugins/sandbox-providers/kubernetes/test/unit/pod-exec.test.ts
@@ -116,6 +116,7 @@ describe("execInPod", () => {
     let resolveWebsocket: ((ws: EventEmitter) => void) | undefined;
     let observedStdin = "";
     let observedStdinFinished = false;
+    const ws = Object.assign(new EventEmitter(), { close: vi.fn() });
 
     execMock.mockImplementation((_namespace, _pod, _container, _command, _stdout, _stderr, stdin) => {
       stdin?.on("data", (chunk: Buffer) => {
@@ -132,9 +133,10 @@ describe("execInPod", () => {
     const result = await execInPod({} as never, "ns", "pod-1", "agent", ["base64", "-d"], "abc", 5);
     expect(result.timedOut).toBe(true);
 
-    resolveWebsocket?.(new EventEmitter());
+    resolveWebsocket?.(ws);
     await Promise.resolve();
 
+    expect(ws.close).toHaveBeenCalled();
     expect(observedStdin).toBe("");
     expect(observedStdinFinished).toBe(false);
   });