Description
WordPress is prone to a cross-domain Flash injection vulnerability. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site, allowing the attacker to steal cookie-based authentication credentials, or to fool a user into inserting credentials on a fake Flash form. WordPress versions 4.2.x ranging from 4.2 and up to (and including) 4.2.18 are vulnerable.
Remediation
Update to WordPress version 4.2.19 or latest
References
https://opnsec.com/2017/10/cve-2016-9263-unpatched-xsf-vulnerability-in-wordpress/
https://opnsec.com/2017/10/flashme-wordpress-vulnerability-disclosure-cve-2016-9263/
Related Vulnerabilities
WordPress Plugin Import and export users and customers Multiple Vulnerabilities (1.14.0.2)
Apache Traffic Server Improper Input Validation Vulnerability (CVE-2010-2952)
PHP Use of Externally-Controlled Format String Vulnerability (CVE-2006-0200)
WordPress Plugin Comment Link Remove and Other Comment Tools Cross-Site Request Forgery (2.1.4)
Oracle Application Server Other Vulnerability (CVE-2006-5365)