{"api_version":"1","generated_at":"2026-10-01T02:09:24+00:00","cve":"CVE-2026-97523","urls":{"html":"https://cve.report/CVE-2026-97523","api":"https://cve.report/api/cve/CVE-2026-97523.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-97523","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-97523"},"summary":{"title":"mptcp: close race between scheduler and state change","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: close race between scheduler and state change\n\nThe mptcp scheduler may race with subflow sockets state change: data\ntransmission on the selected socket may fail and a later release could\ntry to use mss_now reset to 0 for a divide operation.\n\nAddress the issue by explicitly checking for the critical scenario.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:02","updated_at":"2026-09-25 15:17:57"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/a09c87abf10a0a7e203137c75b5381aa63d9b31d","name":"https://git.kernel.org/stable/c/a09c87abf10a0a7e203137c75b5381aa63d9b31d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8f11430d51ff8365bc51b670bc3002b65ae4c6b7","name":"https://git.kernel.org/stable/c/8f11430d51ff8365bc51b670bc3002b65ae4c6b7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4c856f3c151a2f3fa237caa651c44015916ca584","name":"https://git.kernel.org/stable/c/4c856f3c151a2f3fa237caa651c44015916ca584","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/42064de57fb83231fcc89663a94885f228a1ee53","name":"https://git.kernel.org/stable/c/42064de57fb83231fcc89663a94885f228a1ee53","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97523","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97523","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c886d70286bf3ad411eb3d689328a67f7102c6ae 8f11430d51ff8365bc51b670bc3002b65ae4c6b7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c886d70286bf3ad411eb3d689328a67f7102c6ae a09c87abf10a0a7e203137c75b5381aa63d9b31d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c886d70286bf3ad411eb3d689328a67f7102c6ae 4c856f3c151a2f3fa237caa651c44015916ca584 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c886d70286bf3ad411eb3d689328a67f7102c6ae 42064de57fb83231fcc89663a94885f228a1ee53 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"97523","cve":"CVE-2026-97523","epss":"0.006030000","percentile":"0.467380000","score_date":"2026-09-27","updated_at":"2026-09-28 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the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: close race between scheduler and state change\n\nThe mptcp scheduler may race with subflow sockets state change: data\ntransmission on the selected socket may fail and a later release could\ntry to use mss_now reset to 0 for a divide operation.\n\nAddress the issue by explicitly checking for the critical scenario."}],"metrics":[{"cvssV3_1":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - mptcp_push_release is reached from __mptcp_push_pending after mptcp_sched_get_send. A remote MPTCP peer changes the selected subflow's sk_state via TCP RST/FIN (tcp_v4_rcv/tcp_rcv_established/tcp_reset) without the msk lock, and a DSS DATA_ACK (mptcp_incoming_options→ack_update_msk) sets MPTCP_PUSH_PENDING so mptcp_release_cb calls that push.\nAC:L - The attacker creates both halves of the race: they induce __mptcp_push_pending (DSS DATA_ACK, or eliciting mptcp_sendmsg) so mptcp_subflow_get_send snapshots __tcp_can_send without the ssk lock, then RST/FIN/MP_FAIL that subflow before lock_sock; the window is attacker-timed and retryable, not an uninfluencable layout.\nPR:N - Completing MP_CAPABLE to an IPPROTO_MPTCP listener needs no account or capability; net.mptcp.enabled defaults to 1 in mptcp pernet init, and tcp_rcv_established/mptcp_incoming_options apply no application credentials before the DATA_ACK and RST/FIN that cause this race.\nUI:N - The attacker sends the DATA_ACK and RST/FIN themselves and supplies the request that makes the service call mptcp_sendmsg; no victim mount, click, or extra confirmation is required.\nS:U - The divide-error runs in tcp_tso_autosize/tcp_set_skb_tso_segs on the host kernel MPTCP/TCP socket; it does not cross a VM, IOMMU, or sandbox boundary.\nC:N - When __tcp_can_send fails in mptcp_sendmsg_frag, info->mss_now stays 0 and tcp_push divides by zero; that CPU exception does not read freed objects or out-of-range kernel memory.\nI:N - tcp_write_xmit aborts on the divide in tcp_tso_autosize/tcp_set_skb_tso_segs before modifying TCP control blocks or packet contents; this is not an OOB/UAF write or control-flow hijack.\nA:H - bytes/mss_now in tcp_tso_autosize and DIV_ROUND_UP(skb->len, mss_now) in tcp_set_skb_tso_segs raise a kernel divide-error oops/panic from mptcp_push_release, and the attacker can repeat it across MPTCP connections."}]}],"providerMetadata":{"dateUpdated":"2026-09-25T14:41:04.318Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/8f11430d51ff8365bc51b670bc3002b65ae4c6b7"},{"url":"https://git.kernel.org/stable/c/a09c87abf10a0a7e203137c75b5381aa63d9b31d"},{"url":"https://git.kernel.org/stable/c/4c856f3c151a2f3fa237caa651c44015916ca584"},{"url":"https://git.kernel.org/stable/c/42064de57fb83231fcc89663a94885f228a1ee53"}],"title":"mptcp: close race between scheduler and state change","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-97523","datePublished":"2026-09-25T10:21:27.042Z","dateReserved":"2026-09-24T16:01:01.152Z","dateUpdated":"2026-09-25T14:41:04.318Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:02","lastModifiedDate":"2026-09-25 15:17:57","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"97523","Ordinal":"1","Title":"mptcp: close race between scheduler and state change","CVE":"CVE-2026-97523","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"97523","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: close race between scheduler and state change\n\nThe mptcp scheduler may race with subflow sockets state change: data\ntransmission on the selected socket may fail and a later release could\ntry to use mss_now reset to 0 for a divide operation.\n\nAddress the issue by explicitly checking for the critical scenario.","Type":"Description","Title":"mptcp: close race between scheduler and state change"}]}}}