{ "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": "2026-10-19T09:08:41.355Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:08:41.355Z" }, "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", "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" }, { "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" } } } }