CVE-2019-20372

Red Hat statement

Ansible Tower 3.5 and 3.6 are not vulnerable by default as are not using error_page variable in the nginx configuration. However, Ansible Tower 3.5 and 3.6 are distributing nginx 1.14 and 1.16 vulnerable versions as a dependency and configuration could be modified making it vulnerable. Red Hat CloudForms Management Engine 5.9 and 5.10 are not vulnerable by default as are not using error_page variable in the nginx configuration. However, both mentioned builds ships vulnerable nginx versions 1.10 and 1.14 respectively. CloudForms 5.11 does not use nginx directly hence it is not vulnerable. Red Hat Quay's configuration of nginx means it's not affected by this issue. It doesn't use error_page to do a 302 redirect. It's only use of error_page uses a named location ie: error_page 404 /404.html; location = /40x.html { } error_page 500 502 503 504 /50x.html; location = /50x.html { }

Red Hat mitigation

To mitigate this issue, use a named location instead of having the error_page handler do the redirect, this configuration is not vulnerable to request smuggling on all versions of NGINX we tested. server { listen 80; server_name localhost; error_page 401 @401; location / { return 401; } location @401 { return 302 http://example.org; } }