{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97523","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-24T16:01:01.152Z","datePublished":"2026-09-25T10:21:27.042Z","dateUpdated":"2026-10-03T10:59:16.541Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-03T10:59:16.541Z"},"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"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"},"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"],"versions":[{"version":"fb9c73ef2ac2ec816efdc8b9267bc04e1369c20b","lessThan":"d74b2e26b54a7dae1d87c1f19ae0d6db500e5e03","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"5883ae880f51edc4b1484e787473b865b6159ead","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"0a926b5df8efdfbac07e2fb7fafb21849a2ad9c0","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"8f11430d51ff8365bc51b670bc3002b65ae4c6b7","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"a09c87abf10a0a7e203137c75b5381aa63d9b31d","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"4c856f3c151a2f3fa237caa651c44015916ca584","status":"affected","versionType":"git"},{"version":"c886d70286bf3ad411eb3d689328a67f7102c6ae","lessThan":"42064de57fb83231fcc89663a94885f228a1ee53","status":"affected","versionType":"git"},{"version":"8caf5c15b5288d52d9c89374d6c10fa32ee84ec5","status":"affected","versionType":"git"},{"version":"5.15.190","lessThan":"5.15.222","status":"affected","versionType":"semver"},{"version":"5.19.4","lessThan":"5.20","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"],"versions":[{"version":"6.0","status":"affected"},{"version":"0","lessThan":"6.0","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc4","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.190","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"7.3-rc4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19.4"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/d74b2e26b54a7dae1d87c1f19ae0d6db500e5e03"},{"url":"https://git.kernel.org/stable/c/5883ae880f51edc4b1484e787473b865b6159ead"},{"url":"https://git.kernel.org/stable/c/0a926b5df8efdfbac07e2fb7fafb21849a2ad9c0"},{"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"}}}}