Hello @autumn-blue, welcome to the community!
You should contact Cisco/a reseller to acquire a new firewall to get around this, if you do have an account manager at Cisco/the reseller you should speak to them re. this as they may be able to give you some assistance.
Also note that the solution to mitigate this risk is listed in the linked bug: "Cisco has released software updates that address this vulnerability and strongly recommends that customers upgrade to a fixed software release. There are no workarounds that address this vulnerability."
Happy to help! Please mark as helpful/solution if applicable.
Get in touch: https://torbjorn.dev
