diff --git a/CHANGELOG.md b/CHANGELOG.md
index 652c7ea7c5..a32c557c94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -74,6 +74,7 @@
 - Fix: プロフィールを編集してもリロードするまで反映されない問題を修正
 - Fix: エラー画像URLを設定した後解除すると，デフォルトの画像が表示されない問題の修正
 - Fix: MkCodeEditorで行がずれていってしまう問題の修正
+- Fix: Summaly proxy利用時にプレイヤーが動作しないことがあるのを修正 #13196
 
 ### Server
 - Enhance: 連合先のレートリミットに引っかかった際にリトライするようになりました
diff --git a/packages/frontend/src/components/MkUrlPreview.vue b/packages/frontend/src/components/MkUrlPreview.vue
index 2dcb5f226d..eb5e90ea9d 100644
--- a/packages/frontend/src/components/MkUrlPreview.vue
+++ b/packages/frontend/src/components/MkUrlPreview.vue
@@ -13,7 +13,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			v-if="player.url.startsWith('http://') || player.url.startsWith('https://')"
 			sandbox="allow-popups allow-scripts allow-storage-access-by-user-activation allow-same-origin"
 			scrolling="no"
-			:allow="player.allow.join(';')"
+			:allow="player.allow == null ? 'autoplay;encrypted-media;fullscreen' : player.allow.filter(x => ['autoplay', 'clipboard-write', 'fullscreen', 'encrypted-media', 'picture-in-picture', 'web-share'].includes(x)).join(';')"
 			:class="$style.playerIframe"
 			:src="player.url + (player.url.match(/\?/) ? '&autoplay=1&auto_play=1' : '?autoplay=1&auto_play=1')"
 			:style="{ border: 0 }"
diff --git a/packages/frontend/test/url-preview.test.ts b/packages/frontend/test/url-preview.test.ts
index 6cf8317c07..b7587754c6 100644
--- a/packages/frontend/test/url-preview.test.ts
+++ b/packages/frontend/test/url-preview.test.ts
@@ -116,6 +116,34 @@ describe('MkUrlPreview', () => {
 		assert.strictEqual(iframe?.allow, 'fullscreen;web-share');
 	});
 
+	test('A Summaly proxy response without allow falls back to the default', async () => {
+		const iframe = await renderAndOpenPreview({
+			url: 'https://example.local',
+			player: {
+				url: 'https://example.local/player',
+				width: null,
+				height: null,
+				allow: undefined as any,
+			},
+		});
+		assert.exists(iframe, 'iframe should exist');
+		assert.strictEqual(iframe?.allow, 'autoplay;encrypted-media;fullscreen');
+	});
+
+	test('Filtering the allow list from the Summaly proxy', async () => {
+		const iframe = await renderAndOpenPreview({
+			url: 'https://example.local',
+			player: {
+				url: 'https://example.local/player',
+				width: null,
+				height: null,
+				allow: ['autoplay', 'camera', 'fullscreen'],
+			},
+		});
+		assert.exists(iframe, 'iframe should exist');
+		assert.strictEqual(iframe?.allow, 'autoplay;fullscreen');
+	});
+
 	test('Having a player width should keep the fixed aspect ratio', async () => {
 		const iframe = await renderAndOpenPreview({
 			url: 'https://example.local',