diff --git a/src/socket/socketclient.js b/src/socket/socketclient.js
index d0ae95a..4f8c603 100644
--- a/src/socket/socketclient.js
+++ b/src/socket/socketclient.js
@@ -765,6 +765,18 @@ export class SocketClient {
     const startToken = {};
     this.scanSessionTokens.set(sessionId, startToken);
 
+    const existing = this.scanSessions.get(sessionId);
+    if (existing?.scanning) {
+      logger.info(
+        "Scan session already running, ignoring duplicate start:",
+        sessionId,
+      );
+      if (typeof callback === "function") {
+        callback({ success: true, sessionId, alreadyRunning: true });
+      }
+      return;
+    }
+
     await this.stopScanSession(sessionId);
 
     if (this.scanSessionTokens.get(sessionId) !== startToken) {