diff --git a/.circleci/config.yml b/.circleci/config.yml
index 87740249862fb..d5c6913975e81 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -872,6 +872,8 @@ jobs:
       - upload-test-results
   test-bun:
     executor: linux-python
+    environment:
+      OVERRIDE_NODE_JS_VERSION: "v24.0.0"
     steps:
       - checkout
       - pip-install
@@ -880,10 +882,14 @@ jobs:
           name: install bun
           command: |
             curl -fsSL https://bun.com/install | bash
-            echo "BUN_ENGINE = os.path.expanduser('~/.bun/bin/bun')" >> ~/emsdk/.emscripten
-            echo "JS_ENGINES = [BUN_ENGINE]" >> ~/emsdk/.emscripten
+            echo "NODE_JS_TEST = os.path.expanduser('~/.bun/bin/bun')" >> ~/emsdk/.emscripten
+            echo "JS_ENGINES = [NODE_JS_TEST]" >> ~/emsdk/.emscripten
       - run-tests:
-          test_targets: "core0.test_hello_world"
+          test_targets: "
+            core0.test_hello_world
+            core0.test_hello_argc_pthreads
+            core2.test_pthread_create
+            "
   test-jsc:
     executor: linux-python
     steps:
diff --git a/src/pthread_esm_startup.mjs b/src/pthread_esm_startup.mjs
index fe53ed6a7e5a0..c28d9f1fdea8c 100644
--- a/src/pthread_esm_startup.mjs
+++ b/src/pthread_esm_startup.mjs
@@ -16,14 +16,17 @@ console.log("Running pthread_esm_startup");
 #if ENVIRONMENT_MAY_BE_NODE
 if ({{{ nodeDetectionCode() }}}) {
   // Create as web-worker-like an environment as we can.
+  globalThis.self = globalThis;
   var worker_threads = await import('worker_threads');
-  global.Worker = worker_threads.Worker;
+  globalThis.Worker = worker_threads.Worker;
   var parentPort = worker_threads['parentPort'];
-  parentPort.on('message', (msg) => global.onmessage?.({ data: msg }));
-  Object.assign(globalThis, {
-    self: global,
-    postMessage: (msg) => parentPort['postMessage'](msg),
-  });
+  // Deno and Bun already have `postMessage` defined on the global scope and
+  // deliver messages to `globalThis.onmessage`, so we must not duplicate that
+  // behavior here if `postMessage` is already present.
+  if (!globalThis.postMessage) {
+    parentPort.on('message', (msg) => globalThis.onmessage?.({ data: msg }));
+    globalThis.postMessage = (msg) => parentPort['postMessage'](msg);
+  }
 }
 #endif
 
diff --git a/src/runtime_common.js b/src/runtime_common.js
index 93523d4e12ecd..62b84cbe10e31 100644
--- a/src/runtime_common.js
+++ b/src/runtime_common.js
@@ -38,12 +38,15 @@ var readyPromiseResolve, readyPromiseReject;
 #if (PTHREADS || WASM_WORKERS) && (ENVIRONMENT_MAY_BE_NODE && !WASM_ESM_INTEGRATION)
 if (ENVIRONMENT_IS_NODE && {{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
   // Create as web-worker-like an environment as we can.
+  globalThis.self = globalThis;
   var parentPort = worker_threads['parentPort'];
-  parentPort.on('message', (msg) => global.onmessage?.({ data: msg }));
-  Object.assign(globalThis, {
-    self: global,
-    postMessage: (msg) => parentPort['postMessage'](msg),
-  });
+  // Deno and Bun already have `postMessage` defined on the global scope and
+  // deliver messages to `globalThis.onmessage`, so we must not duplicate that
+  // behavior here if `postMessage` is already present.
+  if (!globalThis.postMessage) {
+    parentPort.on('message', (msg) => globalThis.onmessage?.({ data: msg }));
+    globalThis.postMessage = (msg) => parentPort['postMessage'](msg);
+  }
   // Node.js Workers do not pass postMessage()s and uncaught exception events to the parent
   // thread necessarily in the same order where they were generated in sequential program order.
   // See https://github.com/nodejs/node/issues/59617
diff --git a/tools/shared.py b/tools/shared.py
index 78be09305ca1d..05077a557294d 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -278,7 +278,11 @@ def env_with_node_in_path():
 
 
 def _get_node_version_pair(nodejs):
-  actual = utils.run_process(nodejs + ['--version'], stdout=PIPE).stdout.strip()
+  override = os.environ.get('OVERRIDE_NODE_JS_VERSION')
+  if override:
+    actual = override
+  else:
+    actual = utils.run_process(nodejs + ['--version'], stdout=PIPE).stdout.strip()
   version = actual.removeprefix('v')
   version = version.split('-')[0].split('.')
   version = tuple(int(v) for v in version)