Description
Due to differences in CouchDB's Erlang-based JSON parser and JavaScript-based JSON parser, it is possible to submit _users documents with duplicate keys for 'roles' used for access control within the database, including the special case '_admin' role, that denotes administrative users. In combination with 'CVE-2017-12636' (Remote Code Execution), this can be used to give non-admin users access to arbitrary shell commands on the server as the database system user.
Remediation
Upgrade to the latest version of CouchDB
References
Related Vulnerabilities
WordPress Plugin PowerPack Pro for Elementor Privilege Escalation (2.10.14)
WordPress Plugin Web Application Firewall-website security Privilege Escalation (2.1.1)
WordPress Plugin Travel Management Privilege Escalation (1.5)
WordPress Plugin Simplr Registration Form Plus+ Privilege Escalation (2.4.3)
WordPress Plugin UserPro-Community and User Profile Privilege Escalation (4.9.20)