For users who obtain Linux through distributions such as Debian, Oracle Linux, SUSE, and Amazon Linux, fixed kernel packages are available for at least some releases. Ubuntu and Red Hat Enterprise Linux, however, had yet to release patched kernels as of October 30.
MCTCP listeners create the remote attack surface
Anthropic’s exploit specifically targets Linux servers running an MPTCP listener. MPTCP extends conventional TCP by allowing a device to use multiple network interfaces simultaneously within a single connection. This enables bandwidth aggregation, improved network selection, and failover when one network path becomes unavailable.
Linux implements MPTCP through its networking stack, but the protocol is opt-in: applications must explicitly request it when creating sockets, although mechanisms such as eBPF and other configuration techniques can also force applications to use it.
