{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-97524", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-24T16:01:01.152Z", "datePublished": "2026-09-25T10:21:27.668Z", "dateUpdated": "2026-09-25T14:41:05.413Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-25T14:41:05.413Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: avoid unneeded actions on subflow reset\n\nOnce in a blue moon, the mptcp receive path can recursively call\nmptcp_data_ready() via state change under unlucky error conditions, and\nthen try to hold the data lock again.\n\nBreak the recursion loop explicitly checking for the exceptional\ncondition.\n\nAdd a new flag instead of using an existing one like 'closing', to exit\nearly in subflow_state_change(), and explicitly flush the RX queue at\nreset time.\n\nThis avoids unneeded processing to check for available data -- calling\nget_mapping_status() and more on a dying subflow -- but also in error\nreporting and worker scheduling.\n\nNote that we must consume the currently peeked skb before invoking\nmptcp_dss_corruption to avoid consuming it again after the eventual\nreset has freed it."}], "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 - A crafted MPTCP DSS option on a received TCP segment is the attacker-controlled input; it is parsed on the established RX path tcp_rcv_established \u2192 tcp_data_queue \u2192 subflow_data_ready \u2192 mptcp_data_ready \u2192 __mptcp_move_skbs_from_subflow, which calls mptcp_dss_corruption() and then the patched mptcp_subflow_reset()/subflow_state_change(). MPTCP/TCP is a routable IP protocol.\nAC:L - The peer disables infinite fallback via MP_JOIN (mptcp_subflow_joined(); allow_join_initial_addr_port defaults to 1) or by filling msk->out_of_order_queue, then sends a DSS with data_len shorter than the skb plus another TCP-ofo segment so map_remaining < len in __mptcp_move_skbs_from_subflow() calls mptcp_subflow_reset() while ssk->sk_receive_queue is still occupied, making subflow_state_change() re-enter mptcp_data_ready().\nPR:N - The DSS is processed in TCP receive softirq after an unauthenticated MP_CAPABLE handshake with an IPPROTO_MPTCP listener (or an outbound MPTCP client); no local account, capability, or application credential is checked on the path to mptcp_dss_corruption().\nUI:N - The attacker\u2019s DSS segments are handled entirely in RX softirq on an existing MPTCP connection; no local user mount, file open, or other victim action is required.\nS:U - The recursive mptcp_data_lock hang and subflow teardown stay inside the victim kernel\u2019s network stack; no VM, IOMMU, or sandbox boundary is crossed.\nC:N - The defect is a nested spin_lock_bh on sk->sk_lock.slock from subflow_state_change() back into mptcp_data_ready(); it does not read attacker-chosen kernel memory or leak pointers.\nI:N - Pre-fix tcp_done() does not purge ssk->sk_receive_queue, and the nested mptcp_data_ready() never proceeds past the already-held slock, so there is no use-after-free, write primitive, or control-flow hijack.\nA:H - mptcp_data_ready() already holds mptcp_data_lock (spin_lock_bh on sk->sk_lock.slock) when mptcp_dss_corruption() \u2192 mptcp_subflow_reset() \u2192 tcp_done() invokes subflow_state_change(), which re-enters mptcp_data_ready() and deadlocks the CPU in softirq (soft lockup)."}]}], "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", "net/mptcp/protocol.h", 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"b8be15d1ae7ea4eedd547c3b3141f592fbddcd30", "status": "affected", "versionType": "git"}, {"version": "8bfd391bde685df7289b928ce8876a3583be4bfb", "status": "affected", "versionType": "git"}, {"version": "5.10.228", "lessThan": "5.11", "status": "affected", "versionType": "semver"}, {"version": "5.15.169", "lessThan": "5.16", "status": "affected", "versionType": "semver"}, {"version": "6.1.113", "lessThan": "6.2", "status": "affected", "versionType": "semver"}, {"version": "6.6.57", "lessThan": "6.7", "status": "affected", "versionType": "semver"}, {"version": "6.11.4", "lessThan": "6.12", "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", "net/mptcp/protocol.h", "net/mptcp/subflow.c"], "versions": [{"version": "6.12", "status": "affected"}, {"version": "0", "lessThan": "6.12", "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": "6.12", "versionEndExcluding": "6.12.111"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.18.53"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "7.2.7"}, {"vulnerable": true, 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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/mptcp/protocol.c", "net/mptcp/protocol.h", "net/mptcp/subflow.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "4b7abdcb5ba832fafab679f0d998af39cbc99307", "status": "affected", "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "versionType": "git"}, {"lessThan": "b2dbcc1ed48b5ac070a41db4a52aade6823c4df0", "status": "affected", "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "versionType": "git"}, {"lessThan": "ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f", "status": "affected", "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "versionType": "git"}, {"lessThan": "2b0f561f21b27c40c91ea4975268a06092bd7e9c", "status": "affected", "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "versionType": "git"}, {"status": "affected", "version": "fde99e972b8f88cebe619241d7aa43d288ef666a", "versionType": "git"}, {"status": "affected", "version": "12c1676d598e3b8dd92a033b623b792cc2ea1ec5", "versionType": "git"}, {"status": "affected", "version": "35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25", "versionType": "git"}, {"status": "affected", "version": "b8be15d1ae7ea4eedd547c3b3141f592fbddcd30", "versionType": "git"}, {"status": "affected", "version": "8bfd391bde685df7289b928ce8876a3583be4bfb", "versionType": "git"}, {"lessThan": "5.11", "status": "affected", "version": "5.10.228", "versionType": "semver"}, {"lessThan": "5.16", "status": "affected", "version": "5.15.169", "versionType": "semver"}, {"lessThan": "6.2", "status": "affected", "version": "6.1.113", "versionType": "semver"}, {"lessThan": "6.7", "status": "affected", "version": "6.6.57", "versionType": "semver"}, {"lessThan": "6.12", "status": "affected", "version": "6.11.4", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/mptcp/protocol.c", "net/mptcp/protocol.h", "net/mptcp/subflow.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.12"}, {"lessThan": "6.12", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.111", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.53", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.7", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc4", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: avoid unneeded actions on subflow reset\n\nOnce in a blue moon, the mptcp receive path can recursively call\nmptcp_data_ready() via state change under unlucky error conditions, and\nthen try to hold the data lock again.\n\nBreak the recursion loop explicitly checking for the exceptional\ncondition.\n\nAdd a new flag instead of using an existing one like 'closing', to exit\nearly in subflow_state_change(), and explicitly flush the RX queue at\nreset time.\n\nThis avoids unneeded processing to check for available data -- calling\nget_mapping_status() and more on a dying subflow -- but also in error\nreporting and worker scheduling.\n\nNote that we must consume the currently peeked skb before invoking\nmptcp_dss_corruption to avoid consuming it again after the eventual\nreset has freed it."}], "id": "CVE-2026-97524", "lastModified": "2026-09-25T11:17:02.520", "metrics": {}, "published": "2026-09-25T11:17:02.520", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2b0f561f21b27c40c91ea4975268a06092bd7e9c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4b7abdcb5ba832fafab679f0d998af39cbc99307"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b2dbcc1ed48b5ac070a41db4a52aade6823c4df0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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