https://vulnerability.circl.lu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Tue, 29 Sep 2026 11:35:37 +0000 https://vulnerability.circl.lu/vuln/cve-2026-80585 <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>mptcp: fastopen: only mark MPTFO subflows with SYN data</p> <p>Passive TCP Fast Open accepts a valid-cookie SYN even when it carries no data. In that case the child socket&#39;s receive queue is intentionally left empty.</p> <p>mptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking for queued SYN data. That made data-less TFO SYNs hit a WARN and, if the warning was non-fatal, left stale MPTFO state behind. The stale flag could later trigger a state-confusion bug in check_fully_established().</p> <p>Only mark the subflow as MPTFO after confirming that an SKB was queued. Return quietly when the receive queue is empty.</p> <p>Note that mptcp_subflow_context&#39;s is_mptfo field is now not just about subflows where the TFO was present, but about MPTFO subflow that consumed SYN data. Only having a valid cookie but not carrying data is not really &#34;doing TFO&#34;.</p> <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>mptcp: fastopen: only mark MPTFO subflows with SYN data</p> <p>Passive TCP Fast Open accepts a valid-cookie SYN even when it carries no data. In that case the child socket&#39;s receive queue is intentionally left empty.</p> <p>mptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking for queued SYN data. That made data-less TFO SYNs hit a WARN and, if the warning was non-fatal, left stale MPTFO state behind. The stale flag could later trigger a state-confusion bug in check_fully_established().</p> <p>Only mark the subflow as MPTFO after confirming that an SKB was queued. Return quietly when the receive queue is empty.</p> <p>Note that mptcp_subflow_context&#39;s is_mptfo field is now not just about subflows where the TFO was present, but about MPTFO subflow that consumed SYN data. Only having a valid cookie but not carrying data is not really &#34;doing TFO&#34;.</p> https://vulnerability.circl.lu/vuln/cve-2026-80585