diff --git a/locales/index.d.ts b/locales/index.d.ts
index 981c0f15aa..071629296e 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -9842,6 +9842,21 @@ export interface Locale extends ILocale {
          */
         "summaryProxyDescription2": string;
     };
+    "_urlWarning": {
+        /**
+         * 外部サイトに移動します
+         */
+        "title": string;
+        /**
+         * 別のサイトに移動しようとしています。
+         * リンク先の安全性を十分に確認した上で進んでください。
+         */
+        "description": string;
+        /**
+         * 今後{domain}のリンクを信頼する
+         */
+        "trustThisDomain": ParameterizedString<"domain">;
+    };
 }
 declare const locales: {
     [lang: string]: Locale;
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index db877de7e8..e024d22b06 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -2621,3 +2621,8 @@ _urlPreviewSetting:
   summaryProxy: "プレビューを生成するプロキシのエンドポイント"
   summaryProxyDescription: "Misskey本体ではなく、サマリープロキシを使用してプレビューを生成します。"
   summaryProxyDescription2: "プロキシには下記パラメータがクエリ文字列として連携されます。プロキシ側がこれらをサポートしない場合、設定値は無視されます。"
+
+_urlWarning:
+  title: "外部サイトに移動します"
+  description: "別のサイトに移動しようとしています。\nリンク先の安全性を十分に確認した上で進んでください。"
+  trustThisDomain: "今後{domain}のリンクを信頼する"
diff --git a/packages/frontend/src/components/MkUrlWarningDialog.vue b/packages/frontend/src/components/MkUrlWarningDialog.vue
new file mode 100644
index 0000000000..de0df86e72
--- /dev/null
+++ b/packages/frontend/src/components/MkUrlWarningDialog.vue
@@ -0,0 +1,136 @@
+<!--
+SPDX-FileCopyrightText: syuilo and misskey-project
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<MkModal ref="modal" :preferType="'dialog'" :zPriority="'high'" @click="done(true)" @closed="emit('closed')">
+	<div :class="$style.root" class="_gaps">
+		<div class="_gaps_s">
+			<div :class="$style.icon">
+				<i :class="$style.iconInner" class="ti ti-alert-triangle"></i>
+			</div>
+			<header :class="$style.title">{{ i18n.ts._urlWarning.title }}</header>
+			<div><Mfm :text="i18n.ts._urlWarning.description"/></div>
+			<div class="_monospace" :class="$style.urlAddress">{{ url }}</div>
+			<div>
+				<MkSwitch v-model="trustThisDomain">{{ i18n.tsx._urlWarning.trustThisDomain({ domain }) }}</MkSwitch>
+			</div>
+		</div>
+		<div :class="$style.buttons">
+			<MkButton data-cy-modal-dialog-ok inline primary rounded @click="ok">{{ i18n.ts.ok }}</MkButton>
+			<MkButton data-cy-modal-dialog-cancel inline rounded @click="cancel">{{ i18n.ts.cancel }}</MkButton>
+		</div>
+	</div>
+</MkModal>
+</template>
+
+<script lang="ts" setup>
+import { onBeforeUnmount, onMounted, ref, shallowRef, computed } from 'vue';
+import MkModal from '@/components/MkModal.vue';
+import MkButton from '@/components/MkButton.vue';
+import MkSwitch from '@/components/MkSwitch.vue';
+import { i18n } from '@/i18n.js';
+import { defaultStore } from '@/store.js';
+
+type Result = string | number | true | null;
+
+const props = withDefaults(defineProps<{
+	url: string;
+	openInNewTab?: boolean;
+}>(), {
+	openInNewTab: true,
+});
+
+const emit = defineEmits<{
+	(ev: 'done', v: { canceled: true } | { canceled: false, result: Result }): void;
+	(ev: 'closed'): void;
+}>();
+
+const modal = shallowRef<InstanceType<typeof MkModal>>();
+const trustThisDomain = ref(false);
+
+const domain = computed(() => new URL(props.url).hostname);
+
+// overload function を使いたいので lint エラーを無視する
+function done(canceled: true): void;
+function done(canceled: false, result: Result): void; // eslint-disable-line no-redeclare
+function done(canceled: boolean, result?: Result): void { // eslint-disable-line no-redeclare
+	emit('done', { canceled, result } as { canceled: true } | { canceled: false, result: Result });
+	modal.value?.close();
+}
+
+async function ok() {
+	const result = true;
+	if (!defaultStore.state.trustedDomains.includes(domain.value) && trustThisDomain.value) {
+		await defaultStore.set('trustedDomains', defaultStore.state.trustedDomains.concat(domain.value));
+	}
+	done(false, result);
+}
+
+function cancel() {
+	done(true);
+}
+
+/*
+function onBgClick() {
+	if (props.cancelableByBgClick) cancel();
+}
+*/
+function onKeydown(evt: KeyboardEvent) {
+	if (evt.key === 'Escape') cancel();
+}
+
+onMounted(() => {
+	document.addEventListener('keydown', onKeydown);
+});
+
+onBeforeUnmount(() => {
+	document.removeEventListener('keydown', onKeydown);
+});
+</script>
+
+<style lang="scss" module>
+.root {
+	position: relative;
+	margin: auto;
+	padding: 32px;
+	width: 100%;
+	min-width: 320px;
+	max-width: 480px;
+	box-sizing: border-box;
+	text-align: center;
+	background: var(--panel);
+	border-radius: 16px;
+}
+
+.icon {
+	font-size: 24px;
+	color: var(--warn);
+}
+
+.iconInner {
+	display: block;
+	margin: 0 auto;
+}
+
+.title {
+	font-weight: bold;
+	font-size: 1.1em;
+}
+
+.urlAddress {
+	padding: 8px;
+	border-radius: calc(var(--radius) / 2);
+	border: 1px solid var(--divider);
+	overflow-x: auto;
+	white-space: nowrap;
+}
+
+.buttons {
+	display: flex;
+	gap: 8px;
+	flex-wrap: wrap;
+	justify-content: center;
+}
+</style>
diff --git a/packages/frontend/src/store.ts b/packages/frontend/src/store.ts
index 7742acc60d..c2ee298b7b 100644
--- a/packages/frontend/src/store.ts
+++ b/packages/frontend/src/store.ts
@@ -132,6 +132,10 @@ export const defaultStore = markRaw(new Storage('base', {
 		where: 'account',
 		default: [] as string[],
 	},
+	trustedDomains: {
+		where: 'account',
+		default: [] as string[],
+	},
 
 	menu: {
 		where: 'deviceAccount',