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 3.8.x ranging from 3.8 and up to (and including) 3.8.24 are vulnerable.
Remediation
Update to WordPress version 3.8.25 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 Stylish Price List Security Bypass (6.8.14)
Joomla Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2011-2488)
Mailman Other Vulnerability (CVE-2001-1132)
WordPress Plugin Docket Cache-Object Cache Accelerator Cross-Site Scripting (21.08.01)
WordPress Plugin WP SVG Icons Cross-Site Request Forgery (3.2.1)