diff --git a/CONFIG.md b/CONFIG.md
index 43a72cc..c7f5596 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -5,6 +5,7 @@ You can configure MailHog using command line options or environment variables:
 
 | Environment         | Command line  | Default         | Description
 | ------------------- | ------------- | --------------- | -----------
+| MH_CORS_ORIGIN      | -cors-origin  |                 | If set, a Access-Control-Allow-Origin header is returned for API endpoints
 | MH_HOSTNAME         | -hostname     | mailhog.example | Hostname to use for EHLO/HELO and message IDs
 | MH_HTTP_BIND_ADDR   | -httpbindaddr | 0.0.0.0:8025    | Interface and port for HTTP server to bind to
 | MH_MONGO_COLLECTION | -mongocoll    | messages        | MongoDB collection name for message storage