In Apache httpd 2.4.0 to 2.4.29, when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a Session header. This comes from the HTTP_SESSION variable name used by mod_session to forward its data to CGIs, since the prefix HTTP_ is also used by the Apache HTTP Server to pass HTTP header fields, per CGI specifications. https://nvd.nist.gov/vuln/detail/CVE-2018-1283