diff --git a/fluxer_desktop/src/main/IpcHandlers.ts b/fluxer_desktop/src/main/IpcHandlers.ts
index 190bdde95..dc5fc9ed1 100644
--- a/fluxer_desktop/src/main/IpcHandlers.ts
+++ b/fluxer_desktop/src/main/IpcHandlers.ts
@@ -35,6 +35,7 @@ import {openExternalDeduped} from '@electron/main/OpenExternal';
 import {getStatus as getOpenH264Status, setEnabled as setOpenH264Enabled} from '@electron/main/OpenH264Manager';
 import {registerPasskeyHandlers} from '@electron/main/Passkeys';
 import {getAppMetricsSnapshot, getDesktopInfo, getGpuInfo} from '@electron/main/PlatformInfo';
+import {requirePrivilegedRendererDocumentSender} from '@electron/main/PrivilegedRendererDocuments';
 import {getStreamerModeCaptureAppStatus} from '@electron/main/StreamerModeProcessDetection';
 import {
 	acquireStreamingPriority,
@@ -347,7 +348,8 @@ export function registerIpcHandlers(): void {
 	ipcMain.handle('clipboard-read-text', (): string => {
 		return clipboard.readText();
 	});
-	ipcMain.handle('clipboard-write-file', async (_event, rawOptions: unknown): Promise<ClipboardWriteFileResult> => {
+	ipcMain.handle('clipboard-write-file', async (event, rawOptions: unknown): Promise<ClipboardWriteFileResult> => {
+		requirePrivilegedRendererDocumentSender(event, 'clipboard-write-file');
 		try {
 			return await copyRemoteFileToClipboard(parseClipboardWriteFileOptions(rawOptions));
 		} catch (error) {
@@ -355,6 +357,7 @@ export function registerIpcHandlers(): void {
 		}
 	});
 	ipcMain.handle('clipboard-paste', (event): void => {
+		requirePrivilegedRendererDocumentSender(event, 'clipboard-paste');
 		event.sender.paste();
 	});
 	ipcMain.handle(
@@ -386,6 +389,7 @@ export function registerIpcHandlers(): void {
 				defaultPath: string;
 			},
 		): Promise<DownloadFileResult> => {
+			requirePrivilegedRendererDocumentSender(event, 'download-file');
 			const win = BrowserWindow.fromWebContents(event.sender);
 			if (!win) {
 				return {success: false, error: 'No window found'};
diff --git a/fluxer_desktop/src/main/NativeScreenCapture.test.mjs b/fluxer_desktop/src/main/NativeScreenCapture.test.mjs
index 095b7d597..24c9e2e77 100644
--- a/fluxer_desktop/src/main/NativeScreenCapture.test.mjs
+++ b/fluxer_desktop/src/main/NativeScreenCapture.test.mjs
@@ -150,6 +150,9 @@ function loadNativeScreenCapture({platform = 'linux', addon, tccStatus = 'not-de
 				normalizeScreenCaptureDimension: (value) => value,
 			};
 		}
+		if (specifier === './PrivilegedRendererDocuments') {
+			return {requirePrivilegedRendererDocumentSender: () => {}};
+		}
 		throw new Error(`Unexpected import: ${specifier}`);
 	}
 
diff --git a/fluxer_desktop/src/main/NativeScreenCapture.ts b/fluxer_desktop/src/main/NativeScreenCapture.ts
index 017f2230b..9cd52cade 100644
--- a/fluxer_desktop/src/main/NativeScreenCapture.ts
+++ b/fluxer_desktop/src/main/NativeScreenCapture.ts
@@ -19,6 +19,7 @@ import type {
 import {ipcMain} from 'electron';
 import {getTccStatus} from './MacTcc';
 import {isValidStartOptions, normalizeScreenCaptureDimension} from './NativeScreenCaptureValidation';
+import {requirePrivilegedRendererDocumentSender} from './PrivilegedRendererDocuments';
 
 const logger = createChildLogger('NativeScreenCapture');
 const requireModule = createRequire(import.meta.url);
@@ -944,14 +945,16 @@ export function registerNativeScreenCaptureHandlers(): void {
 		'native-screen-capture:get-availability',
 		(): Promise<NativeScreenCaptureAvailability> => getNativeScreenCaptureAvailability(),
 	);
-	ipcMain.handle(
-		'native-screen-capture:list-sources',
-		(): Promise<Array<NativeScreenCaptureSource>> => listNativeScreenCaptureSources(),
-	);
+	ipcMain.handle('native-screen-capture:list-sources', (event): Promise<Array<NativeScreenCaptureSource>> => {
+		requirePrivilegedRendererDocumentSender(event, 'native-screen-capture:list-sources');
+		return listNativeScreenCaptureSources();
+	});
 	ipcMain.handle(
 		'native-screen-capture:start',
-		(event, options: NativeScreenCaptureStartOptions): Promise<NativeScreenCaptureStartResult> =>
-			startNativeScreenCapture(event.sender, options),
+		(event, options: NativeScreenCaptureStartOptions): Promise<NativeScreenCaptureStartResult> => {
+			requirePrivilegedRendererDocumentSender(event, 'native-screen-capture:start');
+			return startNativeScreenCapture(event.sender, options);
+		},
 	);
 	ipcMain.handle(
 		'native-screen-capture:get-diagnostics',
diff --git a/fluxer_desktop/src/main/NotificationsIpc.ts b/fluxer_desktop/src/main/NotificationsIpc.ts
index 20873a325..757ea8e59 100644
--- a/fluxer_desktop/src/main/NotificationsIpc.ts
+++ b/fluxer_desktop/src/main/NotificationsIpc.ts
@@ -7,6 +7,7 @@ import type {NotificationOptions} from '@electron/common/Types';
 import {getNativeNotificationsMode} from '@electron/main/LaunchOptions';
 import {resolveNotificationIcon} from '@electron/main/NotificationIcon';
 import {shouldPlayNotificationSound} from '@electron/main/NotificationState';
+import {requirePrivilegedRendererDocumentSender} from '@electron/main/PrivilegedRendererDocuments';
 import {type BrowserWindow, ipcMain, Notification, nativeImage} from 'electron';
 
 const logger = createChildLogger('Notifications');
@@ -319,11 +320,12 @@ export function registerNotificationIpcHandlers(getMainWindow: () => BrowserWind
 	ipcMain.handle(
 		'show-notification',
 		async (
-			_event,
+			event,
 			options: NotificationOptions,
 		): Promise<{
 			id: string;
 		}> => {
+			requirePrivilegedRendererDocumentSender(event, 'show-notification');
 			const id = getNotificationId(options);
 			if (process.platform === 'linux') {
 				await showLinuxNativeNotification(id, options, getMainWindow);
diff --git a/fluxer_desktop/src/main/PrivilegedRendererDocuments.ts b/fluxer_desktop/src/main/PrivilegedRendererDocuments.ts
new file mode 100644
index 000000000..bade5b587
--- /dev/null
+++ b/fluxer_desktop/src/main/PrivilegedRendererDocuments.ts
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {isTrustedOrigin} from '@electron/main/Window';
+import type {IpcMainInvokeEvent} from 'electron';
+
+export class UntrustedRendererDocumentSenderError extends Error {
+	public constructor(channel: string) {
+		super(`${channel} is only reachable from a trusted top-level renderer document`);
+		this.name = 'UntrustedRendererDocumentSenderError';
+	}
+}
+
+function isPrivilegedRendererDocumentSender(event: IpcMainInvokeEvent): boolean {
+	const frame = event.senderFrame;
+	if (frame == null) {
+		return false;
+	}
+	try {
+		if (frame.detached) {
+			return false;
+		}
+		if (frame.parent != null) {
+			return false;
+		}
+		return isTrustedOrigin(frame.url);
+	} catch {
+		return false;
+	}
+}
+
+export function requirePrivilegedRendererDocumentSender(event: IpcMainInvokeEvent, channel: string): void {
+	if (!isPrivilegedRendererDocumentSender(event)) {
+		throw new UntrustedRendererDocumentSenderError(channel);
+	}
+}
diff --git a/fluxer_desktop/src/main/Window.ts b/fluxer_desktop/src/main/Window.ts
index 8f820773c..7ee41e11d 100644
--- a/fluxer_desktop/src/main/Window.ts
+++ b/fluxer_desktop/src/main/Window.ts
@@ -106,7 +106,7 @@ function getOrigin(url?: string): string | null {
 	}
 }
 
-function isTrustedOrigin(url?: string): boolean {
+export function isTrustedOrigin(url?: string): boolean {
 	const origin = getOrigin(url);
 	if (!origin) return false;
 	if (trustedWebOrigins.has(origin)) return true;