{ "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": "2026-10-19T09:08:42.302Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:08:42.302Z" }, "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 → tcp_data_queue → subflow_data_ready → mptcp_data_ready → __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’s 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’s 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() → mptcp_subflow_reset() → 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", "net/mptcp/subflow.c" ], "versions": [ { "version": "fde99e972b8f88cebe619241d7aa43d288ef666a", "lessThan": "6d669c740933124eae3df8cfc15995af9bcc6aba", "status": "affected", "versionType": "git" }, { "version": "12c1676d598e3b8dd92a033b623b792cc2ea1ec5", "lessThan": "83a7dcdd2b1060484528da70a643125174d47e5a", "status": "affected", "versionType": "git" }, { "version": "35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25", "lessThan": "a370e56024df0b07e3120c45a9773ae123819fd6", "status": "affected", "versionType": "git" }, { "version": "b8be15d1ae7ea4eedd547c3b3141f592fbddcd30", "lessThan": "1962841387087970d75ba8b8d4c2aa2d45705e50", "status": "affected", "versionType": "git" }, { "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "lessThan": "4b7abdcb5ba832fafab679f0d998af39cbc99307", "status": "affected", "versionType": "git" }, { "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "lessThan": "b2dbcc1ed48b5ac070a41db4a52aade6823c4df0", "status": "affected", "versionType": "git" }, { "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "lessThan": "ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f", "status": "affected", "versionType": "git" }, { "version": "e32d262c89e2b22cb0640223f953b548617ed8a6", "lessThan": "2b0f561f21b27c40c91ea4975268a06092bd7e9c", "status": "affected", "versionType": "git" }, { "version": "8bfd391bde685df7289b928ce8876a3583be4bfb", "status": "affected", "versionType": "git" }, { "version": "5.10.228", "lessThan": "5.10.271", "status": "affected", "versionType": "semver" }, { "version": "5.15.169", "lessThan": "5.15.222", "status": "affected", "versionType": "semver" }, { "version": "6.1.113", "lessThan": "6.1.189", "status": "affected", "versionType": "semver" }, { "version": "6.6.57", "lessThan": "6.6.158", "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": "5.10.271", "lessThanOrEqual": "5.10.*", "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": "5.10.228", "versionEndExcluding": "5.10.271" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.169", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.113", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.57", "versionEndExcluding": "6.6.158" }, { "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, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/6d669c740933124eae3df8cfc15995af9bcc6aba" }, { "url": "https://git.kernel.org/stable/c/83a7dcdd2b1060484528da70a643125174d47e5a" }, { "url": "https://git.kernel.org/stable/c/a370e56024df0b07e3120c45a9773ae123819fd6" }, { "url": "https://git.kernel.org/stable/c/1962841387087970d75ba8b8d4c2aa2d45705e50" }, { "url": "https://git.kernel.org/stable/c/4b7abdcb5ba832fafab679f0d998af39cbc99307" }, { "url": "https://git.kernel.org/stable/c/b2dbcc1ed48b5ac070a41db4a52aade6823c4df0" }, { "url": "https://git.kernel.org/stable/c/ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f" }, { "url": "https://git.kernel.org/stable/c/2b0f561f21b27c40c91ea4975268a06092bd7e9c" } ], "title": "mptcp: avoid unneeded actions on subflow reset", "x_generator": { "engine": "bippy-1.2.0" } } } }