Fix permissive CORS policy that allows cross-origin attacks

The on_prepare handler unconditionally reflected the Origin request
header into Access-Control-Allow-Origin, and Socket.IO was configured
with cors_allowed_origins='*'. This allowed any website to make
authenticated cross-origin requests to all API endpoints, enabling
cross-origin download initiation, cookie overwrite, and data deletion.

Replace the blanket origin reflection with an explicit allowlist via
the CORS_ALLOWED_ORIGINS environment variable. When unset, cross-origin
requests are denied by default. Users who need cross-origin access can
set CORS_ALLOWED_ORIGINS to a comma-separated list of trusted origins.
This commit is contained in:
az10b
2026-04-09 19:45:51 -05:00
committed by aazad
parent 0b3645aea1
commit 0072d3488a
+6 -3
View File
@@ -60,6 +60,7 @@ class Config:
'YTDL_OPTIONS_PRESETS': '{}',
'YTDL_OPTIONS_PRESETS_FILE': '',
'ALLOW_YTDL_OPTIONS_OVERRIDES': 'false',
'CORS_ALLOWED_ORIGINS': '',
'ROBOTS_TXT': '',
'HOST': '0.0.0.0',
'PORT': '8081',
@@ -223,7 +224,8 @@ class ObjectSerializer(json.JSONEncoder):
serializer = ObjectSerializer()
app = web.Application()
sio = socketio.AsyncServer(cors_allowed_origins='*')
_cors_origins = [o.strip() for o in config.CORS_ALLOWED_ORIGINS.split(',') if o.strip()] if config.CORS_ALLOWED_ORIGINS else []
sio = socketio.AsyncServer(cors_allowed_origins=_cors_origins if _cors_origins else [])
sio.attach(app, socketio_path=config.URL_PREFIX + 'socket.io')
routes = web.RouteTableDef()
VALID_SUBTITLE_FORMATS = {'srt', 'txt', 'vtt', 'ttml', 'sbv', 'scc', 'dfxp'}
@@ -912,8 +914,9 @@ app.router.add_route('OPTIONS', config.URL_PREFIX + 'upload-cookies', add_cors)
app.router.add_route('OPTIONS', config.URL_PREFIX + 'delete-cookies', add_cors)
async def on_prepare(request, response):
if 'Origin' in request.headers:
response.headers['Access-Control-Allow-Origin'] = request.headers['Origin']
origin = request.headers.get('Origin')
if origin and _cors_origins and origin in _cors_origins:
response.headers['Access-Control-Allow-Origin'] = origin
response.headers['Access-Control-Allow-Headers'] = 'Content-Type'
app.on_response_prepare.append(on_prepare)