diff --git a/src/services/javascriptSandbox.js b/src/services/javascriptSandbox.js
index ad4d443..aac2e16 100644
--- a/src/services/javascriptSandbox.js
+++ b/src/services/javascriptSandbox.js
@@ -144,6 +144,12 @@ function spawnWorker(vfsRoot, googleAuthId) {
             return;
         }
 
+        // Permanent listener: without it an error emitted while the thread is idle (no job
+        // listener attached) is unhandled and takes down the whole process.
+        entry.worker.on('error', (err) => {
+            console.error('[sandbox] worker error:', err?.message || err);
+            dropWorker(entry);
+        });
         entry.worker.on('message', onBooted);
         entry.worker.on('error', onError);
         entry.worker.on('exit', onExit);