{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-80585 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-80585 is a critical vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-80585 and fix it if it is affected.\n\nWhat it is: CVE-2026-80585 is a critical vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-80585 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-80585/ (Markdown: https://insights.sbomify.com/CVE-2026-80585/index.md)","id":"CVE-2026-80585","markdown":"https://insights.sbomify.com/CVE-2026-80585/index.md","name":"CVE-2026-80585","record":{"aliases":["AZL-97842","BELL-CVE-2026-80585","DEBIAN-CVE-2026-80585","GHSA-xhvw-vpqw-3xgx","UBUNTU-CVE-2026-80585"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel MPTCP","requires_auth":"none","summary":"A logic error in Linux kernel MPTCP handling of data-less TCP Fast Open SYNs can cause kernel warnings and potential state confusion, leading to denial of service.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":9.4,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fastopen: only mark MPTFO subflows with SYN data\n\nPassive TCP Fast Open accepts a valid-cookie SYN even when it carries\nno data. In that case the child socket's receive queue is intentionally\nleft empty.\n\nmptcp_fastopen_subflow_synack_set_params() set is_mptfo before checking\nfor queued SYN data. That made data-less TFO SYNs hit a WARN and, if\nthe warning was non-fatal, left stale MPTFO state behind. The stale\nflag could later trigger a state-confusion bug in\ncheck_fully_established().\n\nOnly mark the subflow as MPTFO after confirming that an SKB was queued.\nReturn quietly when the receive queue is empty.\n\nNote that mptcp_subflow_context's is_mptfo field is now not just about\nsubflows where the TFO was present, but about MPTFO subflow that\nconsumed SYN data. Only having a valid cookie but not carrying data is\nnot really \"doing TFO\".","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"mptcp: fastopen: only mark MPTFO subflows with SYN data","id":"CVE-2026-80585","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"other","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"mptcp: options: reset DSS fields in case of unexpected size","id":"CVE-2026-80586"},"packages":[],"prev":{"headline":"s390/qeth: validate user buffer length in SNMP and ARP query ioctls","id":"CVE-2026-80584"},"products":["Linux"],"published":"2026-08-26","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-16","vendors":["Linux"]},"summary":"A logic error in Linux kernel MPTCP handling of data-less TCP Fast Open SYNs can cause kernel warnings and potential state confusion, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2026-80585/"}