diff --git a/packages/frontend/src/components/MkDriveFileThumbnail.vue b/packages/frontend/src/components/MkDriveFileThumbnail.vue
index 2c47a70970..eb93aaab6e 100644
--- a/packages/frontend/src/components/MkDriveFileThumbnail.vue
+++ b/packages/frontend/src/components/MkDriveFileThumbnail.vue
@@ -4,7 +4,13 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
-<div ref="thumbnail" :class="$style.root">
+<div
+	ref="thumbnail"
+	:class="[
+		$style.root,
+		{ [$style.sensitiveHighlight]: highlightWhenSensitive && file.isSensitive },
+	]"
+>
 	<ImgWithBlurhash v-if="isThumbnailAvailable" :hash="file.blurhash" :src="file.thumbnailUrl" :alt="file.name" :title="file.name" :cover="fit !== 'contain'"/>
 	<i v-else-if="is === 'image'" class="ti ti-photo" :class="$style.icon"></i>
 	<i v-else-if="is === 'video'" class="ti ti-video" :class="$style.icon"></i>
@@ -27,6 +33,7 @@ import ImgWithBlurhash from '@/components/MkImgWithBlurhash.vue';
 const props = defineProps<{
 	file: Misskey.entities.DriveFile;
 	fit: 'cover' | 'contain';
+	highlightWhenSensitive?: boolean;
 }>();
 
 const is = computed(() => {
@@ -67,6 +74,18 @@ const isThumbnailAvailable = computed(() => {
 	overflow: clip;
 }
 
+.sensitiveHighlight::after {
+	content: "";
+	position: absolute;
+	top: 0;
+	left: 0;
+	width: 100%;
+	height: 100%;
+	pointer-events: none;
+	border-radius: inherit;
+	box-shadow: inset 0 0 0 4px var(--warn);
+}
+
 .iconSub {
 	position: absolute;
 	width: 30%;
diff --git a/packages/frontend/src/components/MkFileListForAdmin.vue b/packages/frontend/src/components/MkFileListForAdmin.vue
index 30822ef655..13295c455b 100644
--- a/packages/frontend/src/components/MkFileListForAdmin.vue
+++ b/packages/frontend/src/components/MkFileListForAdmin.vue
@@ -14,7 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			class="file _button"
 		>
 			<div v-if="file.isSensitive" class="sensitive-label">{{ i18n.ts.sensitive }}</div>
-			<MkDriveFileThumbnail class="thumbnail" :file="file" fit="contain"/>
+			<MkDriveFileThumbnail class="thumbnail" :file="file" fit="contain" :highlightWhenSensitive="true"/>
 			<div v-if="viewMode === 'list'" class="body">
 				<div>
 					<small style="opacity: 0.7;">{{ file.name }}</small>