CVE-2026-97524
📛 CVE Title
mptcp: avoid unneeded actions on subflow reset
Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: avoid unneeded actions on subflow reset Once in a blue moon, the mptcp receive path can recursively call mptcp_data_ready() via state change under unlucky error conditions, and then try to hold the data lock again. Break the recursion loop explicitly checking for the exceptional condition. Add a new flag instead of using an existing one like 'closing', to exit early in subflow_state_change(), and explicitly flush the RX queue at reset time. This avoids unneeded processing to check for available data -- calling get_mapping_status() and more on a dying subflow -- but also in error reporting and worker scheduling. Note that we must consume the currently peeked skb before invoking mptcp_dss_corruption to avoid consuming it again after the eventual reset has freed it.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- Linux
- CVSS severity
- HIGH
- CVSS score
- 7.5 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Effective score
- 7.5 / 10 HIGH source: CNA overview
- CWE(s)
- —
- Reserved
- 2026-09-24
- Published
- 2026-09-25 10:21 UTC
- Last updated
- 2026-09-25 14:41 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/97xxx/CVE-2026-97524.json
- Linked Threat
- CVE-2026-97524 — mptcp: avoid unneeded actions on subflow reset
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-09-25 11:17:02 UTC
- NVD last modified
- 2026-09-25 15:17:57 UTC
- NVD CVSS v3.1
- 7.5 / 10 HIGH source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Exploitability subscore
- 3.9 / 10
- Impact subscore
- 3.6 / 10
NVD / KEV / EPSS data refreshed 2026-09-26 04:35 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
Affected products (2)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Linux | Linux |
e32d262c89e2b22cb0640223f953b548617ed8a6 (affected),
e32d262c89e2b22cb0640223f953b548617ed8a6 (affected),
e32d262c89e2b22cb0640223f953b548617ed8a6 (affected),
e32d262c89e2b22cb0640223f953b548617ed8a6 (affected),
fde99e972b8f88cebe619241d7aa43d288ef666a (affected),
12c1676d598e3b8dd92a033b623b792cc2ea1ec5 (affected),
35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25 (affected),
b8be15d1ae7ea4eedd547c3b3141f592fbddcd30 (affected),
8bfd391bde685df7289b928ce8876a3583be4bfb (affected),
5.10.228 (affected),
5.15.169 (affected),
6.1.113 (affected),
6.6.57 (affected),
6.11.4 (affected)
|
— |
| Linux | Linux |
6.12 (affected),
0 (unaffected),
6.12.111 (unaffected),
6.18.53 (unaffected),
7.2.7 (unaffected),
7.3-rc4 (unaffected)
|
— |
Vendor references (4)
References embedded in the original CVE record by the assigning CNA.
Web references (0)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
No web references attached yet.
NVD-tagged references (4)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://git.kernel.org/stable/c/2b0f561f21b27c40c91ea4975268a06092bd7e9c 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/4b7abdcb5ba832fafab679f0d998af39cbc99307 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/b2dbcc1ed48b5ac070a41db4a52aade6823c4df0 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f 416baaa9-dc9f-4396-8d5f-8c081fb06d67
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-97524.json.
{
"containers": {
"cna": {
"affected": [
{
"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": [
{
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"versionType": "git"
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{
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{
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"versionType": "git"
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{
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"version": "fde99e972b8f88cebe619241d7aa43d288ef666a",
"versionType": "git"
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{
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{
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"version": "35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25",
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},
{
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"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"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.111",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.53",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.7",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3-rc4",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.10.228",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.15.169",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.1.113",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.6.57",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.11.4",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"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)."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-25T14:41:05.413Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"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": {
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}
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-97524",
"datePublished": "2026-09-25T10:21:27.668Z",
"dateReserved": "2026-09-24T16:01:01.152Z",
"dateUpdated": "2026-09-25T14:41:05.413Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}