{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-68227", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-16T13:41:40.257Z", "datePublished": "2025-12-16T13:57:20.027Z", "dateUpdated": "2026-05-11T21:49:17.263Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:49:17.263Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: Fix proto fallback detection with BPF\n\nThe sockmap feature allows bpf syscall from userspace, or based\non bpf sockops, replacing the sk_prot of sockets during protocol stack\nprocessing with sockmap's custom read/write interfaces.\n'''\ntcp_rcv_state_process()\n syn_recv_sock()/subflow_syn_recv_sock()\n tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)\n bpf_skops_established <== sockops\n bpf_sock_map_update(sk) <== call bpf helper\n tcp_bpf_update_proto() <== update sk_prot\n'''\n\nWhen the server has MPTCP enabled but the client sends a TCP SYN\nwithout MPTCP, subflow_syn_recv_sock() performs a fallback on the\nsubflow, replacing the subflow sk's sk_prot with the native sk_prot.\n'''\nsubflow_syn_recv_sock()\n subflow_ulp_fallback()\n subflow_drop_ctx()\n mptcp_subflow_ops_undo_override()\n'''\n\nThen, this subflow can be normally used by sockmap, which replaces the\nnative sk_prot with sockmap's custom sk_prot. The issue occurs when the\nuser executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops().\nHere, it uses sk->sk_prot to compare with the native sk_prot, but this\nis incorrect when sockmap is used, as we may incorrectly set\nsk->sk_socket->ops.\n\nThis fix uses the more generic sk_family for the comparison instead.\n\nAdditionally, this also prevents a WARNING from occurring:\n\nresult from ./scripts/decode_stacktrace.sh:\n------------[ cut here ]------------\nWARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \\\n(net/mptcp/protocol.c:4005)\nModules linked in:\n...\n\nPKRU: 55555554\nCall Trace:\n<TASK>\ndo_accept (net/socket.c:1989)\n__sys_accept4 (net/socket.c:2028 net/socket.c:2057)\n__x64_sys_accept (net/socket.c:2067)\nx64_sys_call (arch/x86/entry/syscall_64.c:41)\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\nRIP: 0033:0x7f87ac92b83d\n\n---[ end trace 0000000000000000 ]---"}], "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": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "7ee8f015eb47907745e2070184a8ab1e442ac3c4", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "344974ea1a3ca30e4920687b0091bda4438cebdb", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "037cc50589643342d69185b663ecf9d26cce91e8", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "9b1980b6f23fa30bf12add19f37c7458625099eb", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00", "status": "affected", "versionType": "git"}, {"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7", "lessThan": "c77b3b79a92e3345aa1ee296180d1af4e7031f8f", "status": "affected", "versionType": "git"}]}, {"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": "5.7", "status": "affected"}, {"version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.247", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.197", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.118", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.10", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "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": "5.7", "versionEndExcluding": "5.10.247"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.197"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.159"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.118"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.60"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.17.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c"}, {"url": "https://git.kernel.org/stable/c/7ee8f015eb47907745e2070184a8ab1e442ac3c4"}, {"url": "https://git.kernel.org/stable/c/344974ea1a3ca30e4920687b0091bda4438cebdb"}, {"url": "https://git.kernel.org/stable/c/037cc50589643342d69185b663ecf9d26cce91e8"}, {"url": "https://git.kernel.org/stable/c/9b1980b6f23fa30bf12add19f37c7458625099eb"}, {"url": "https://git.kernel.org/stable/c/1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00"}, {"url": "https://git.kernel.org/stable/c/c77b3b79a92e3345aa1ee296180d1af4e7031f8f"}], "title": "mptcp: Fix proto fallback detection with BPF", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: Fix proto fallback detection with BPF\n\nThe sockmap feature allows bpf syscall from userspace, or based\non bpf sockops, replacing the sk_prot of sockets during protocol stack\nprocessing with sockmap's custom read/write interfaces.\n'''\ntcp_rcv_state_process()\n syn_recv_sock()/subflow_syn_recv_sock()\n tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)\n bpf_skops_established <== sockops\n bpf_sock_map_update(sk) <== call bpf helper\n tcp_bpf_update_proto() <== update sk_prot\n'''\n\nWhen the server has MPTCP enabled but the client sends a TCP SYN\nwithout MPTCP, subflow_syn_recv_sock() performs a fallback on the\nsubflow, replacing the subflow sk's sk_prot with the native sk_prot.\n'''\nsubflow_syn_recv_sock()\n subflow_ulp_fallback()\n subflow_drop_ctx()\n mptcp_subflow_ops_undo_override()\n'''\n\nThen, this subflow can be normally used by sockmap, which replaces the\nnative sk_prot with sockmap's custom sk_prot. The issue occurs when the\nuser executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops().\nHere, it uses sk->sk_prot to compare with the native sk_prot, but this\nis incorrect when sockmap is used, as we may incorrectly set\nsk->sk_socket->ops.\n\nThis fix uses the more generic sk_family for the comparison instead.\n\nAdditionally, this also prevents a WARNING from occurring:\n\nresult from ./scripts/decode_stacktrace.sh:\n------------[ cut here ]------------\nWARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \\\n(net/mptcp/protocol.c:4005)\nModules linked in:\n...\n\nPKRU: 55555554\nCall Trace:\n<TASK>\ndo_accept (net/socket.c:1989)\n__sys_accept4 (net/socket.c:2028 net/socket.c:2057)\n__x64_sys_accept (net/socket.c:2067)\nx64_sys_call (arch/x86/entry/syscall_64.c:41)\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\nRIP: 0033:0x7f87ac92b83d\n\n---[ end trace 0000000000000000 ]---"}], "id": "CVE-2025-68227", "lastModified": "2026-04-15T00:35:42.020", "metrics": {}, "published": "2025-12-16T14:15:56.307", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/037cc50589643342d69185b663ecf9d26cce91e8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/344974ea1a3ca30e4920687b0091bda4438cebdb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7ee8f015eb47907745e2070184a8ab1e442ac3c4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9b1980b6f23fa30bf12add19f37c7458625099eb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c77b3b79a92e3345aa1ee296180d1af4e7031f8f"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Deferred"}

{"bugzilla": {"description": "kernel: mptcp: Fix proto fallback detection with BPF", "id": "2422658", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2422658"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "details": ["No description is available for this CVE."], "name": "CVE-2025-68227", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-12-16T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-68227\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-68227\nhttps://lore.kernel.org/linux-cve-announce/2025121635-CVE-2025-68227-930f@gregkh/T"], "threat_severity": "Low"}

{}