CVE-2026-80585

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mptcp: fastopen: only mark MPTFO subflows with SYN data<br /> <br /> Passive TCP Fast Open accepts a valid-cookie SYN even when it carries<br /> no data. In that case the child socket&amp;#39;s receive queue is intentionally<br /> left empty.<br /> <br /> mptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking<br /> for queued SYN data. That made data-less TFO SYNs hit a WARN and, if<br /> the warning was non-fatal, left stale MPTFO state behind. The stale<br /> flag could later trigger a state-confusion bug in<br /> check_fully_established().<br /> <br /> Only mark the subflow as MPTFO after confirming that an SKB was queued.<br /> Return quietly when the receive queue is empty.<br /> <br /> Note that mptcp_subflow_context&amp;#39;s is_mptfo field is now not just about<br /> subflows where the TFO was present, but about MPTFO subflow that<br /> consumed SYN data. Only having a valid cookie but not carrying data is<br /> not really "doing TFO".