diff --git a/packages/backend/src/const.ts b/packages/backend/src/const.ts
index 50ccecd571..12eb6126c4 100644
--- a/packages/backend/src/const.ts
+++ b/packages/backend/src/const.ts
@@ -56,6 +56,9 @@ export const FILE_TYPE_BROWSERSAFE = [
 	'video/webm',
 	'audio/webm',
 
+	// MKV files
+	'video/x-matroska',
+
 	'audio/aac',
 
 	// see https://github.com/misskey-dev/misskey/pull/10686
diff --git a/packages/backend/src/core/SearchService.ts b/packages/backend/src/core/SearchService.ts
index 9b9ae27739..60a66d58f7 100644
--- a/packages/backend/src/core/SearchService.ts
+++ b/packages/backend/src/core/SearchService.ts
@@ -34,6 +34,7 @@ type Q =
 	{ op: 'or', qs: Q[] } |
 	{ op: 'not', q: Q };
 
+// Sync with consts.ts and const.ts
 const fileTypes = {
 	image: [
 		'image/webp',
@@ -42,12 +43,20 @@ const fileTypes = {
 		'image/avif',
 		'image/apng',
 		'image/gif',
+		'image/bmp',
+		'image/tiff',
+		'image/x-icon',
 	],
 	video: [
 		'video/mp4',
 		'video/webm',
 		'video/mpeg',
 		'video/x-m4v',
+		'video/ogg',
+		'video/quicktime',
+		'video/3gpp',
+		'video/3gpp2',
+		'video/x-matroska',
 	],
 	audio: [
 		'audio/mpeg',
@@ -58,6 +67,9 @@ const fileTypes = {
 		'audio/opus',
 		'audio/ogg',
 		'audio/x-m4a',
+		'audio/mp4',
+		'audio/x-flac',
+		'audio/vnd.wave',
 		'audio/mod',
 		'audio/s3m',
 		'audio/xm',
diff --git a/packages/frontend-shared/js/const.ts b/packages/frontend-shared/js/const.ts
index 5bbfd314a4..9258814d97 100644
--- a/packages/frontend-shared/js/const.ts
+++ b/packages/frontend-shared/js/const.ts
@@ -40,6 +40,9 @@ export const FILE_TYPE_BROWSERSAFE = [
 	'video/webm',
 	'audio/webm',
 
+	// MKV files
+	'video/x-matroska',
+
 	'audio/aac',
 
 	// see https://github.com/misskey-dev/misskey/pull/10686