CVE-2025-68227
In the Linux kernel, the following vulnerability has been resolved:
mptcp: Fix proto fallback detection with BPF
The sockmap feature allows bpf syscall from userspace, or based on bpf sockops, replacing the sk_prot of sockets during protocol stack processing with sockmap's custom read/write interfaces. ''' tcp_rcv_state_process() syn_recv_sock()/subflow_syn_recv_sock() tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB) bpf_skops_established <== sockops bpf_sock_map_update(sk) <== call bpf helper tcp_bpf_update_proto() <== update sk_prot '''
When the server has MPTCP enabled but the client sends a TCP SYN without MPTCP, subflow_syn_recv_sock() performs a fallback on the subflow, replacing the subflow sk's sk_prot with the native sk_prot.
Leer descripción completaMostrar menos
''' subflow_syn_recv_sock() subflow_ulp_fallback() subflow_drop_ctx() mptcp_subflow_ops_undo_override() '''
Then, this subflow can be normally used by sockmap, which replaces the native sk_prot with sockmap's custom sk_prot. The issue occurs when the user executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops(). Here, it uses sk->sk_prot to compare with the native sk_prot, but this is incorrect when sockmap is used, as we may incorrectly set sk->sk_socket->ops.
This fix uses the more generic sk_family for the comparison instead.
Additionally, this also prevents a WARNING from occurring:
result from ./scripts/decode_stacktrace.sh: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \ (net/mptcp/protocol.c:4005) Modules linked in: ...
PKRU: 55555554 Call Trace: <TASK> do_accept (net/socket.c:1989) __sys_accept4 (net/socket.c:2028 net/socket.c:2057) __x64_sys_accept (net/socket.c:2067) x64_sys_call (arch/x86/entry/syscall_64.c:41) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f87ac92b83d
Detalles técnicos trazas, registros y código del informe original
---[ end trace 0000000000000000 ]---
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.22%
- Percentil entre todas las CVEs puntuadas: 11
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/037cc50589643342d69185b663ecf9d26cce91e8
- https://git.kernel.org/stable/c/1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00
- https://git.kernel.org/stable/c/344974ea1a3ca30e4920687b0091bda4438cebdb
- https://git.kernel.org/stable/c/7ee8f015eb47907745e2070184a8ab1e442ac3c4
- https://git.kernel.org/stable/c/92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c
- https://git.kernel.org/stable/c/9b1980b6f23fa30bf12add19f37c7458625099eb
- https://git.kernel.org/stable/c/c77b3b79a92e3345aa1ee296180d1af4e7031f8f
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-68227",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c",
"versionType": "git"
},
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "7ee8f015eb47907745e2070184a8ab1e442ac3c4",
"versionType": "git"
},
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
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"versionType": "git"
},
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "037cc50589643342d69185b663ecf9d26cce91e8",
"versionType": "git"
},
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "9b1980b6f23fa30bf12add19f37c7458625099eb",
"versionType": "git"
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{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00",
"versionType": "git"
},
{
"status": "affected",
"version": "0b4f33def7bbde1ce2fea05f116639270e7acdc7",
"lessThan": "c77b3b79a92e3345aa1ee296180d1af4e7031f8f",
"versionType": "git"
}
],
"programFiles": [
"net/mptcp/protocol.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.247",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.197",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.159",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.118",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.60",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.17.10",
"versionType": "semver",
"lessThanOrEqual": "6.17.*"
},
{
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/mptcp/protocol.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-12-16T14:15:56.307",
"references": [
{
"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",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"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 ]---"
}
],
"lastModified": "2026-06-17T09:58:46.060",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}