diff --git a/CHANGELOG.md b/CHANGELOG.md
index 09b5a2ac87c382876c38310494ce4dd0d0a976ad..6e1e87d80b4aac8051e66de1149507eb97ac1cf6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,8 @@
 
 ### Bugfixes
 - アップロードエラー時の処理を修正
+- Add `img-src` and `media-src` directives to `Content-Security-Policy` for
+  files and media proxy
 
 ## 12.101.1 (2021/12/29)
 
diff --git a/packages/backend/src/server/file/index.ts b/packages/backend/src/server/file/index.ts
index a455acd1cf006a3f9e3c6622c46978d837395106..6fe6110dc94b1b718297681a69822435b6977744 100644
--- a/packages/backend/src/server/file/index.ts
+++ b/packages/backend/src/server/file/index.ts
@@ -18,7 +18,7 @@ const _dirname = dirname(_filename);
 const app = new Koa();
 app.use(cors());
 app.use(async (ctx, next) => {
-	ctx.set('Content-Security-Policy', `default-src 'none'; style-src 'unsafe-inline'`);
+	ctx.set('Content-Security-Policy', `default-src 'none'; img-src 'self'; media-src 'self'; style-src 'unsafe-inline'`);
 	await next();
 });
 
diff --git a/packages/backend/src/server/proxy/index.ts b/packages/backend/src/server/proxy/index.ts
index b8993f19f8818fe1544783a8082c3fdab348c3e2..7a3094311cf5867ba7ccd73711e3901456be7675 100644
--- a/packages/backend/src/server/proxy/index.ts
+++ b/packages/backend/src/server/proxy/index.ts
@@ -11,7 +11,7 @@ import { proxyMedia } from './proxy-media';
 const app = new Koa();
 app.use(cors());
 app.use(async (ctx, next) => {
-	ctx.set('Content-Security-Policy', `default-src 'none'; style-src 'unsafe-inline'`);
+	ctx.set('Content-Security-Policy', `default-src 'none'; img-src 'self'; media-src 'self'; style-src 'unsafe-inline'`);
 	await next();
 });