diff --git a/src/canvas-host/a2ui/.bundle.hash b/src/canvas-host/a2ui/.bundle.hash
index 19a232f5c..586ab5545 100644
--- a/src/canvas-host/a2ui/.bundle.hash
+++ b/src/canvas-host/a2ui/.bundle.hash
@@ -1 +1 @@
-2567ca5bbc065b922d96717a488d5db3120b5b033c5d0508682d1aa8fbba470a
+098343e65655850312863011a5c06be0ee15d31a815e6150f65cbd101306f5b3
diff --git a/src/web/accounts.ts b/src/web/accounts.ts
index 3af151526..4e39b4d30 100644
--- a/src/web/accounts.ts
+++ b/src/web/accounts.ts
@@ -85,8 +85,18 @@ function resolveAccountConfig(
   return entry;
 }
 
+/**
+ * Normalize accountId to prevent path traversal attacks.
+ * Strips any characters that could be used to escape the directory structure.
+ */
+function normalizeAccountId(accountId: string): string {
+  const trimmed = accountId.trim();
+  if (!trimmed) return "default";
+  return trimmed.replace(/[^a-z0-9._-]+/gi, "_");
+}
+
 function resolveDefaultAuthDir(accountId: string): string {
-  return path.join(resolveOAuthDir(), "whatsapp", accountId);
+  return path.join(resolveOAuthDir(), "whatsapp", normalizeAccountId(accountId));
 }
 
 function resolveLegacyAuthDir(): string {