diff --git a/packages/frontend/apps/electron/src/main/helper-process.ts b/packages/frontend/apps/electron/src/main/helper-process.ts
index 13a00e2d0..d395d05fa 100644
--- a/packages/frontend/apps/electron/src/main/helper-process.ts
+++ b/packages/frontend/apps/electron/src/main/helper-process.ts
@@ -21,6 +21,7 @@ import type { HelperToMain, MainToHelper } from '../shared/type';
 import { MessageEventChannel } from '../shared/utils';
 import { beforeAppQuit } from './cleanup';
 import { logger } from './logger';
+import { openExternalSafely } from './security/open-external';
 
 const HELPER_PROCESS_PATH = path.join(__dirname, './helper.js');
 
@@ -105,10 +106,10 @@ class HelperProcessManager {
         return dialog.showSaveDialog(window, opts);
       },
     };
-    const shellMethods = pickAndBind(shell, [
-      'openExternal',
-      'showItemInFolder',
-    ]);
+    const shellMethods = {
+      openExternal: openExternalSafely as typeof shell.openExternal,
+      showItemInFolder: shell.showItemInFolder.bind(shell),
+    };
     const appMethods = pickAndBind(app, ['getPath']);
 
     const mainToHelperServer: MainToHelper = {
diff --git a/packages/frontend/apps/electron/src/main/recording/index.ts b/packages/frontend/apps/electron/src/main/recording/index.ts
index 20dc99de1..6e836a884 100644
--- a/packages/frontend/apps/electron/src/main/recording/index.ts
+++ b/packages/frontend/apps/electron/src/main/recording/index.ts
@@ -7,6 +7,7 @@ import path from 'node:path';
 import { shell } from 'electron';
 
 import { isMacOS } from '../../shared/utils';
+import { openExternalSafely } from '../security/open-external';
 import type { NamespaceHandlers } from '../type';
 import {
   askForMeetingPermission,
@@ -87,7 +88,9 @@ export const recordingHandlers = {
         microphone: 'Privacy_Microphone',
       };
       const url = `x-apple.systempreferences:com.apple.preference.security?${urlMap[type]}`;
-      return shell.openExternal(url);
+      return openExternalSafely(url, {
+        additionalProtocols: ['x-apple.systempreferences:'],
+      });
     }
     // this only available on MacOS
     return false;
diff --git a/packages/frontend/apps/electron/src/main/security-restrictions.ts b/packages/frontend/apps/electron/src/main/security-restrictions.ts
index 4d14daf7e..ad0ce46ee 100644
--- a/packages/frontend/apps/electron/src/main/security-restrictions.ts
+++ b/packages/frontend/apps/electron/src/main/security-restrictions.ts
@@ -1,4 +1,35 @@
-import { app, shell } from 'electron';
+import { app } from 'electron';
+
+import { openExternalSafely } from './security/open-external';
+
+const extractRedirectTarget = (rawUrl: string) => {
+  try {
+    const parsed = new URL(rawUrl);
+    const redirectUri = parsed.searchParams.get('redirect_uri');
+    if (redirectUri) {
+      return redirectUri;
+    }
+
+    if (parsed.hash) {
+      const hash = parsed.hash.startsWith('#')
+        ? parsed.hash.slice(1)
+        : parsed.hash;
+
+      const queryIndex = hash.indexOf('?');
+      if (queryIndex !== -1) {
+        const hashParams = new URLSearchParams(hash.slice(queryIndex + 1));
+        const hashRedirect = hashParams.get('redirect_uri');
+        if (hashRedirect) {
+          return hashRedirect;
+        }
+      }
+    }
+
+    return null;
+  } catch {
+    return null;
+  }
+};
 
 app.on('web-contents-created', (_, contents) => {
   const isInternalUrl = (url: string) => {
@@ -18,7 +49,9 @@ app.on('web-contents-created', (_, contents) => {
     }
     // Prevent navigation
     event.preventDefault();
-    shell.openExternal(url).catch(console.error);
+    openExternalSafely(url).catch(error => {
+      console.error('[security] Failed to open external URL:', error);
+    });
   });
 
   /**
@@ -32,9 +65,22 @@ app.on('web-contents-created', (_, contents) => {
    * @see https://www.electronjs.org/docs/latest/tutorial/security#15-do-not-use-openexternal-with-untrusted-content
    */
   contents.setWindowOpenHandler(({ url }) => {
-    if (!isInternalUrl(url) || url.includes('/redirect-proxy')) {
-      // Open default browser
-      shell.openExternal(url).catch(console.error);
+    if (!isInternalUrl(url)) {
+      openExternalSafely(url).catch(error => {
+        console.error('[security] Failed to open external URL:', error);
+      });
+    } else if (url.includes('/redirect-proxy')) {
+      const redirectTarget = extractRedirectTarget(url);
+      if (redirectTarget) {
+        openExternalSafely(redirectTarget).catch(error => {
+          console.error('[security] Failed to open external URL:', error);
+        });
+      } else {
+        console.warn(
+          '[security] Blocked redirect proxy with missing redirect target:',
+          url
+        );
+      }
     }
     // Prevent creating new window in application
     return { action: 'deny' };
diff --git a/packages/frontend/apps/electron/src/main/security/open-external.ts b/packages/frontend/apps/electron/src/main/security/open-external.ts
new file mode 100644
index 000000000..1bd55b28e
--- /dev/null
+++ b/packages/frontend/apps/electron/src/main/security/open-external.ts
@@ -0,0 +1,52 @@
+import { shell } from 'electron';
+
+const DEFAULT_ALLOWED_PROTOCOLS = new Set(['http:', 'https:', 'mailto:']);
+
+export interface OpenExternalOptions {
+  additionalProtocols?: string[];
+}
+
+export const isAllowedExternalUrl = (
+  rawUrl: string,
+  additionalProtocols: Iterable<string> = []
+) => {
+  try {
+    const parsed = new URL(rawUrl);
+    const protocol = parsed.protocol.toLowerCase();
+    if (DEFAULT_ALLOWED_PROTOCOLS.has(protocol)) {
+      return true;
+    }
+
+    for (const extra of additionalProtocols) {
+      if (protocol === extra.toLowerCase()) {
+        return true;
+      }
+    }
+
+    return false;
+  } catch (error) {
+    console.warn('[security] Failed to parse external URL', rawUrl, error);
+    return false;
+  }
+};
+
+export const openExternalSafely = async (
+  rawUrl: string,
+  options: OpenExternalOptions = {}
+) => {
+  const { additionalProtocols = [] } = options;
+
+  if (!isAllowedExternalUrl(rawUrl, additionalProtocols)) {
+    console.warn('[security] Blocked attempt to open external URL:', rawUrl);
+    return;
+  }
+
+  try {
+    await shell.openExternal(rawUrl);
+  } catch (error) {
+    console.error('[security] Failed to open external URL:', rawUrl, error);
+  }
+};
+export const ALLOWED_EXTERNAL_PROTOCOLS: ReadonlySet<string> = new Set(
+  DEFAULT_ALLOWED_PROTOCOLS
+);
diff --git a/packages/frontend/apps/electron/src/main/ui/handlers.ts b/packages/frontend/apps/electron/src/main/ui/handlers.ts
index e1251eb46..ef4ce03ba 100644
--- a/packages/frontend/apps/electron/src/main/ui/handlers.ts
+++ b/packages/frontend/apps/electron/src/main/ui/handlers.ts
@@ -1,9 +1,10 @@
-import { app, clipboard, nativeImage, nativeTheme, shell } from 'electron';
+import { app, clipboard, nativeImage, nativeTheme } from 'electron';
 import { getLinkPreview } from 'link-preview-js';
 
 import { isMacOS } from '../../shared/utils';
 import { persistentConfig } from '../config-storage/persist';
 import { logger } from '../logger';
+import { openExternalSafely } from '../security/open-external';
 import type { WorkbenchViewMeta } from '../shared-state-schema';
 import type { NamespaceHandlers } from '../type';
 import {
@@ -151,7 +152,7 @@ export const uiHandlers = {
     }
   },
   openExternal(_, url: string) {
-    return shell.openExternal(url);
+    return openExternalSafely(url);
   },
 
   // tab handlers
diff --git a/packages/frontend/core/src/desktop/pages/redirect/index.tsx b/packages/frontend/core/src/desktop/pages/redirect/index.tsx
index 3405d237d..c5c5e5d8e 100644
--- a/packages/frontend/core/src/desktop/pages/redirect/index.tsx
+++ b/packages/frontend/core/src/desktop/pages/redirect/index.tsx
@@ -14,6 +14,7 @@ const trustedDomain = [
 ];
 
 const logger = new DebugLogger('redirect_proxy');
+const ALLOWED_PROTOCOLS = new Set(['http:', 'https:']);
 
 /**
  * /redirect-proxy page
@@ -32,6 +33,11 @@ export const loader: LoaderFunction = async ({ request }) => {
   try {
     const target = new URL(redirectUri);
 
+    if (!ALLOWED_PROTOCOLS.has(target.protocol)) {
+      logger.warn('Blocked redirect with disallowed protocol', target.protocol);
+      return { allow: false };
+    }
+
     if (
       target.hostname === window.location.hostname ||
       trustedDomain.some(domain =>
@@ -46,7 +52,8 @@ export const loader: LoaderFunction = async ({ request }) => {
     return { allow: false };
   }
 
-  return { allow: true };
+  logger.warn('Blocked redirect to untrusted domain', redirectUri);
+  return { allow: false };
 };
 
 export const Component = () => {
diff --git a/packages/frontend/core/src/modules/url/services/url.ts b/packages/frontend/core/src/modules/url/services/url.ts
index b764f3ac1..be9731f35 100644
--- a/packages/frontend/core/src/modules/url/services/url.ts
+++ b/packages/frontend/core/src/modules/url/services/url.ts
@@ -39,6 +39,16 @@ export class UrlService extends Service {
    * @param url only full url with http/https protocol is supported
    */
   openExternal(url: string) {
+    let parsed: URL;
+    try {
+      parsed = new URL(url);
+    } catch {
+      throw new Error(`Invalid external URL: ${url}`);
+    }
+
+    if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
+      throw new Error('only http/https URLs are supported');
+    }
     if (BUILD_CONFIG.isWeb || BUILD_CONFIG.isMobileWeb) {
       location.href = url;
     } else {