Description
WordPress Plugin Ultimate Member-User Profile, Registration, Login, Member Directory, Content Restriction & Membership is prone to a vulnerability that lets attackers upload arbitrary files because the application fails to properly verify user-supplied input. An attacker can exploit this vulnerability to upload arbitrary code and run it in the context of the webserver process. This may facilitate unauthorized access or privilege escalation; other attacks are also possible. WordPress Plugin Ultimate Member-User Profile, Registration, Login, Member Directory, Content Restriction & Membership version 2.0.21 is vulnerable; prior versions may also be affected.
Remediation
Update to plugin version 2.0.22 or latest
References
https://blog.nintechnet.com/arbitrary-file-upload-vulnerability-in-wordpress-ultimate-member-plugin/
https://wordpress.org/support/topic/danger-security-issue/
https://wordpress.org/support/topic/appears-um-got-hacked-on-my-site/
https://wordpress.org/support/topic/malware-files-being-uploaded/
https://plugins.svn.wordpress.org/ultimate-member/trunk/readme.txt
Related Vulnerabilities
WordPress 4.3.x Cross-Site Scripting Vulnerability (4.3 - 4.3.3)
WordPress Plugin WP Safe Search 'v1' Parameter Cross-Site Scripting (0.7)
WordPress Plugin Bulk Datetime Change Security Bypass (1.11)
WordPress Plugin Style It Cross-Site Scripting (1.0)
Drupal Core 4.7.x Cross-Site Request Forgery (4.7.0 - 4.7.3)