Interestingly, Android is the only operating system that fully immunizes VPN apps from the attack because it doesn’t implement option 121. For all other OSes, there are no complete fixes. When apps run on Linux there’s a setting that minimizes the effects, but even then TunnelVision can be used to exploit a side channel that can be used to de-anonymize destination traffic and perform targeted denial-of-service attacks.
I did not look into that setting that minimises the effect but from the way it’s written it sounds like this isn’t used by default, so by default you’re still vulnerable. Add even if it’s on, there’s still a side vulnerability.
https://arstechnica.com/security/2024/05/novel-attack-against-virtually-all-vpn-apps-neuters-their-entire-purpose/
I did not look into that setting that minimises the effect but from the way it’s written it sounds like this isn’t used by default, so by default you’re still vulnerable. Add even if it’s on, there’s still a side vulnerability.