diff --git a/lib/__tests__/jmap-vacation-capability.test.ts b/lib/__tests__/jmap-vacation-capability.test.ts
new file mode 100644
index 000000000..0d6d04c92
--- /dev/null
+++ b/lib/__tests__/jmap-vacation-capability.test.ts
@@ -0,0 +1,43 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { JMAPClient } from '../jmap/client';
+
+const VACATION = 'urn:ietf:params:jmap:vacationresponse';
+
+// Stalwart lists vacationresponse in the session capabilities for everyone,
+// and in the account's own only when the user may read the reply (#1488).
+async function connect(accountCapabilities: Record<string, unknown>): Promise<JMAPClient> {
+  vi.spyOn(globalThis, 'fetch').mockResolvedValueOnce(new Response(JSON.stringify({
+    capabilities: {
+      'urn:ietf:params:jmap:core': {},
+      'urn:ietf:params:jmap:mail': {},
+      [VACATION]: {},
+    },
+    accounts: {
+      'acct-1': { name: 'user@test.com', isPersonal: true, accountCapabilities },
+    },
+    primaryAccounts: { 'urn:ietf:params:jmap:mail': 'acct-1' },
+    apiUrl: 'https://mail.example.com/jmap/api',
+    downloadUrl: 'https://mail.example.com/jmap/download/{accountId}/{blobId}/{name}',
+    uploadUrl: 'https://mail.example.com/jmap/upload/{accountId}/',
+    eventSourceUrl: 'https://mail.example.com/jmap/eventsource',
+  }), { status: 200, headers: { 'Content-Type': 'application/json' } }));
+  const client = new JMAPClient('https://mail.example.com', 'user@test.com', 'pass123');
+  await client.connect();
+  return client;
+}
+
+describe('JMAPClient.supportsVacationResponse', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('is true when the account lists the capability', async () => {
+    const client = await connect({ 'urn:ietf:params:jmap:mail': {}, [VACATION]: {} });
+    expect(client.supportsVacationResponse()).toBe(true);
+  });
+
+  it('is false when only the session lists it (permission revoked)', async () => {
+    const client = await connect({ 'urn:ietf:params:jmap:mail': {} });
+    expect(client.supportsVacationResponse()).toBe(false);
+  });
+});
diff --git a/lib/jmap/client.ts b/lib/jmap/client.ts
index cdec1af22..2d7adf72b 100644
--- a/lib/jmap/client.ts
+++ b/lib/jmap/client.ts
@@ -6808,8 +6808,12 @@ export class JMAPClient implements IJMAPClient {
     return this.hasCapability("urn:ietf:params:jmap:quota");
   }
 
+  /**
+   * Stalwart keeps vacationresponse in the session-wide capabilities but drops
+   * it from the account's own when the user lacks the permission (#1488).
+   */
   supportsVacationResponse(): boolean {
-    return this.hasCapability("urn:ietf:params:jmap:vacationresponse");
+    return this.accountSupports(this.accountId, "urn:ietf:params:jmap:vacationresponse");
   }
 
   /**