diff --git a/nginx/snippets/security-headers.conf b/nginx/snippets/security-headers.conf
index c0a7198..c4755d2 100644
--- a/nginx/snippets/security-headers.conf
+++ b/nginx/snippets/security-headers.conf
@@ -1,4 +1,5 @@
 add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
+add_header Cross-Origin-Opener-Policy "same-origin" always;
 add_header X-Content-Type-Options "nosniff" always;
 
 # obsolete when client system time is correct