A vulnerability in the WebVPN portal login page of the Cisco ASA could allow an unauthenticated, remote attacker to execute cross-site scripting (XSS) attacks or hijack user sessions.
The vulnerability is due to a failure to properly validate user-supplied input in the WebVPN portal login page. An attacker could exploit this vulnerability by convincing a user to click a crafted URL.
Cisco has confirmed this vulnerability in a security notice and software updates are available.
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.