{"id":11981,"date":"2026-09-04T18:54:00","date_gmt":"2026-09-04T10:54:00","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-80585"},"modified":"2026-09-04T18:54:00","modified_gmt":"2026-09-04T10:54:00","slug":"cve-2026-80585","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-80585","title":{"rendered":"CVE-2026-80585 [CRITICAL] &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fastopen: only"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>mptcp: fastopen: only mark MPTFO subflows with SYN data<\/p>\n<p>Passive TCP Fast Open accepts a valid-cookie SYN even when it carries<br \/>\nno data. In that case the child socket&#8217;s receive queue is intentionally<br \/>\nleft empty.<\/p>\n<p>mptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking<br \/>\nfor queued SYN data. That made data-less TFO SYNs hit a WARN and, if<br \/>\nthe warning was non-fatal, left stale MPTFO state behind. The stale<br \/>\nflag could later trigger a state-confusion bug in<br \/>\ncheck_fully_established().<\/p>\n<p>Only mark the subflow as MPTFO after confirming that an SKB was queued.<br \/>\nReturn quietly when the receive queue is empty.<\/p>\n<p>Note that mptcp_subflow_context&#8217;s is_mptfo field is now not just about<br \/>\nsubflows where the TFO was present, but about MPTFO subflow that<br \/>\nconsumed SYN data. Only having a valid cookie but not carrying data is<br \/>\nnot really &#8220;doing TFO&#8221;.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>mptcp: fastopen: only mark MPTFO subflows with SYN data<\/p>\n<p>Passive TCP Fast Open accepts a valid-cookie SYN even when it carries<br \/>\nno d<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-11981","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/11981","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11981"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11981"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11981"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}