There are no workarounds that address this vulnerability. The following two mitigations may help limit exposure to this vulnerability:
Disable Remote Management
Caution: Do not disable remote management if the device is managed via the WAN connection. This will result in loss of management connectivity to the device. Disabling this feature prevents Cisco QuickVPN access.
Remote Management is disabled by default. If it is enabled, administrators can disable it using the Web Access screen: Administration > Management Interface > Web Access. Check the box for Disabled in the Remote Management field.
Disabling remote management helps ensure that only users on the LAN could attempt to exploit the vulnerabilities. Remote management is not enabled by default on the device.
Limit Remote Management Access to Specific IP Addresses
If remote management is required, harden the device so that it can be accessed only by certain IP addresses, rather than the default setting of any. By accessing the configuration screen (Administration > Management Interface > Web Access), an administrator can change the Remote IP address field to ensure only devices with specified IP addresses can access the device.