CVE-2026-31669 (GCVE-0-2026-31669)
Vulnerability from cvelistv5 – Published: 2026-04-24 14:45 – Updated: 2026-09-08 08:47
VLAI
EPSS
VEX
Title
mptcp: fix slab-use-after-free in __inet_lookup_established
Summary
In the Linux kernel, the following vulnerability has been resolved:
mptcp: fix slab-use-after-free in __inet_lookup_established
The ehash table lookups are lockless and rely on
SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability
during RCU read-side critical sections. Both tcp_prot and
tcpv6_prot have their slab caches created with this flag
via proto_register().
However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into
tcpv6_prot_override during inet_init() (fs_initcall, level 5),
before inet6_init() (module_init/device_initcall, level 6) has
called proto_register(&tcpv6_prot). At that point,
tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab
remains NULL permanently.
This causes MPTCP v6 subflow child sockets to be allocated via
kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab
cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so
when these sockets are freed without SOCK_RCU_FREE (which is
cleared for child sockets by design), the memory can be
immediately reused. Concurrent ehash lookups under
rcu_read_lock can then access freed memory, triggering a
slab-use-after-free in __inet_lookup_established.
Fix this by splitting the IPv6-specific initialization out of
mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called
from mptcp_proto_v6_init() before protocol registration. This
ensures tcpv6_prot_override.slab correctly inherits the
SLAB_TYPESAFE_BY_RCU slab cache.
Severity
9.8 (Critical)
Assigner
References
9 references
Impacted products
8 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
b19bc2945b40b9fd38e835700907ffe8534ef0de , < f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47
(git)
Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < fb1f54b7d16f393b8b65d328410f78b4beea8fcc (git) Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < 3fd6547f5b8ac99687be6d937a0321efda760597 (git) Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < eb9c6aeb512f877cf397deb1e4526f646c70e4a7 (git) Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < 15fa9ead4d5e6b6b9c794e84144146c917f2cb62 (git) Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < b313e9037d98c13938740e5ebda7852929366dff (git) Affected: b19bc2945b40b9fd38e835700907ffe8534ef0de , < 9b55b253907e7431210483519c5ad711a37dafa1 (git) |
guessed | |
| Linux | Linux |
Affected:
5.12
Unaffected: 0 , < 5.12 (semver) Unaffected: 5.15.203 , ≤ 5.15.* (semver) Unaffected: 6.1.169 , ≤ 6.1.* (semver) Unaffected: 6.6.135 , ≤ 6.6.* (semver) Unaffected: 6.12.82 , ≤ 6.12.* (semver) Unaffected: 6.18.23 , ≤ 6.18.* (semver) Unaffected: 6.19.13 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix) |
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed | |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed |
{
"containers": {
"adp": [
{
"affected": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-08T08:47:59.039Z",
"orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"shortName": "siemens-SADP"
},
"references": [
{
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
},
{
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
}
],
"x_adpType": "supplier"
}
],
"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": [
{
"lessThan": "f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "fb1f54b7d16f393b8b65d328410f78b4beea8fcc",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "3fd6547f5b8ac99687be6d937a0321efda760597",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "eb9c6aeb512f877cf397deb1e4526f646c70e4a7",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "15fa9ead4d5e6b6b9c794e84144146c917f2cb62",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "b313e9037d98c13938740e5ebda7852929366dff",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "9b55b253907e7431210483519c5ad711a37dafa1",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
}
]
},
{
"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": "5.12"
},
{
"lessThan": "5.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.169",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.135",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.82",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.23",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.169",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.135",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.82",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.23",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.13",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"versionStartIncluding": "5.12",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix slab-use-after-free in __inet_lookup_established\n\nThe ehash table lookups are lockless and rely on\nSLAB_TYPESAFE_BY_RCU to guarantee socket memory stability\nduring RCU read-side critical sections. Both tcp_prot and\ntcpv6_prot have their slab caches created with this flag\nvia proto_register().\n\nHowever, MPTCP\u0027s mptcp_subflow_init() copies tcpv6_prot into\ntcpv6_prot_override during inet_init() (fs_initcall, level 5),\nbefore inet6_init() (module_init/device_initcall, level 6) has\ncalled proto_register(\u0026tcpv6_prot). At that point,\ntcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab\nremains NULL permanently.\n\nThis causes MPTCP v6 subflow child sockets to be allocated via\nkmalloc (falling into kmalloc-4k) instead of the TCPv6 slab\ncache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so\nwhen these sockets are freed without SOCK_RCU_FREE (which is\ncleared for child sockets by design), the memory can be\nimmediately reused. Concurrent ehash lookups under\nrcu_read_lock can then access freed memory, triggering a\nslab-use-after-free in __inet_lookup_established.\n\nFix this by splitting the IPv6-specific initialization out of\nmptcp_subflow_init() into a new mptcp_subflow_v6_init(), called\nfrom mptcp_proto_v6_init() before protocol registration. This\nensures tcpv6_prot_override.slab correctly inherits the\nSLAB_TYPESAFE_BY_RCU slab cache."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Remote IPv6 TCP/MPTCP packets reach `tcp_v6_rcv()` and its lockless established-socket ehash lookup through the normal network receive path. A reachable IPv6 MPTCP service can be exercised over the network without local execution.\nAC:L - The vulnerability is a race between freeing an MPTCP IPv6 child socket and concurrent ehash lookup, but the attacker can drive both sides by repeatedly creating/closing MPTCP connections or subflows while sending packets. Under the required rule, this attacker-controlled race is Low complexity.\nPR:N - No local account, capability, namespace setup, or protocol authentication is needed to send the packets that reach the vulnerable receive path. The only environmental requirement is a reachable MPTCP IPv6 listener.\nUI:N - No victim user action is required after the vulnerable service is listening. Network traffic alone can trigger allocation, teardown, and lookup of the affected sockets.\nS:U - The flaw is in the kernel networking stack and impacts kernel-managed resources within the same security authority. It is not a VM escape, IOMMU bypass, or cross-scope boundary violation.\nC:H - This is a kernel heap use-after-free where freed socket memory can be immediately reused while lockless lookup still dereferences it. Such UAF conditions are defensibly capable of exposing kernel memory or primitives useful for broader disclosure.\nI:H - The stale socket pointer can reference attacker-influenced reused kmalloc memory during refcounting and socket processing. Kernel heap UAF is treated as high integrity impact because it can plausibly be developed into write/control-flow corruption.\nA:H - The reported condition is a slab-use-after-free in `__inet_lookup_established`, which can crash or oops the kernel. A remote attacker can trigger it repeatedly against a reachable affected service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:24:19.282Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47"
},
{
"url": "https://git.kernel.org/stable/c/fb1f54b7d16f393b8b65d328410f78b4beea8fcc"
},
{
"url": "https://git.kernel.org/stable/c/3fd6547f5b8ac99687be6d937a0321efda760597"
},
{
"url": "https://git.kernel.org/stable/c/eb9c6aeb512f877cf397deb1e4526f646c70e4a7"
},
{
"url": "https://git.kernel.org/stable/c/15fa9ead4d5e6b6b9c794e84144146c917f2cb62"
},
{
"url": "https://git.kernel.org/stable/c/b313e9037d98c13938740e5ebda7852929366dff"
},
{
"url": "https://git.kernel.org/stable/c/9b55b253907e7431210483519c5ad711a37dafa1"
}
],
"title": "mptcp: fix slab-use-after-free in __inet_lookup_established",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31669",
"datePublished": "2026-04-24T14:45:17.295Z",
"dateReserved": "2026-03-09T15:48:24.130Z",
"dateUpdated": "2026-09-08T08:47:59.039Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-31669",
"date": "2026-09-21",
"epss": "0.00459",
"percentile": "0.38957"
},
"nvd": {
"cve": {
"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": "f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "fb1f54b7d16f393b8b65d328410f78b4beea8fcc",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "3fd6547f5b8ac99687be6d937a0321efda760597",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "eb9c6aeb512f877cf397deb1e4526f646c70e4a7",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "15fa9ead4d5e6b6b9c794e84144146c917f2cb62",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "b313e9037d98c13938740e5ebda7852929366dff",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
},
{
"lessThan": "9b55b253907e7431210483519c5ad711a37dafa1",
"status": "affected",
"version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
"versionType": "git"
}
]
},
{
"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": "5.12"
},
{
"lessThan": "5.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.169",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.135",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.82",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.23",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
}
],
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "AA3D6441-4F2E-41AB-A26D-388B03A5932F",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "5.12.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "DBEC0E5D-641C-4E98-A6D9-5799B10CE451",
"versionEndExcluding": "6.1.169",
"versionStartIncluding": "5.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "15C1A1B2-14EE-494C-AF3E-D5A7BA640B39",
"versionEndExcluding": "6.6.135",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "02904CAE-71D2-45B3-9EC3-F6A9D18B6307",
"versionEndExcluding": "6.12.82",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "E9E09FDD-9EE3-4A56-92E2-2B30AFD0072F",
"versionEndExcluding": "6.18.23",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "1490EF9B-9080-481C-8D22-1306AAE664E4",
"versionEndExcluding": "6.19.13",
"versionStartIncluding": "6.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:5.12:-:*:*:*:*:*:*",
"matchCriteriaId": "75EB504D-4A83-4C67-9C8D-FD9C6C8EB4CD",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
"matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
"matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
"matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
"matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
"matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
"matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
"matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix slab-use-after-free in __inet_lookup_established\n\nThe ehash table lookups are lockless and rely on\nSLAB_TYPESAFE_BY_RCU to guarantee socket memory stability\nduring RCU read-side critical sections. Both tcp_prot and\ntcpv6_prot have their slab caches created with this flag\nvia proto_register().\n\nHowever, MPTCP\u0027s mptcp_subflow_init() copies tcpv6_prot into\ntcpv6_prot_override during inet_init() (fs_initcall, level 5),\nbefore inet6_init() (module_init/device_initcall, level 6) has\ncalled proto_register(\u0026tcpv6_prot). At that point,\ntcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab\nremains NULL permanently.\n\nThis causes MPTCP v6 subflow child sockets to be allocated via\nkmalloc (falling into kmalloc-4k) instead of the TCPv6 slab\ncache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so\nwhen these sockets are freed without SOCK_RCU_FREE (which is\ncleared for child sockets by design), the memory can be\nimmediately reused. Concurrent ehash lookups under\nrcu_read_lock can then access freed memory, triggering a\nslab-use-after-free in __inet_lookup_established.\n\nFix this by splitting the IPv6-specific initialization out of\nmptcp_subflow_init() into a new mptcp_subflow_v6_init(), called\nfrom mptcp_proto_v6_init() before protocol registration. This\nensures tcpv6_prot_override.slab correctly inherits the\nSLAB_TYPESAFE_BY_RCU slab cache."
}
],
"id": "CVE-2026-31669",
"lastModified": "2026-07-14T13:18:47.573",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-04-24T15:16:46.663",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/15fa9ead4d5e6b6b9c794e84144146c917f2cb62"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/3fd6547f5b8ac99687be6d937a0321efda760597"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/9b55b253907e7431210483519c5ad711a37dafa1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/b313e9037d98c13938740e5ebda7852929366dff"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/eb9c6aeb512f877cf397deb1e4526f646c70e4a7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/fb1f54b7d16f393b8b65d328410f78b4beea8fcc"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-416"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-07-06T19:35:23+00:00",
"cve": "CVE-2026-31669",
"id": "CVE-2026-31669",
"initial_release_date": "2026-04-24T00:00:00+00:00",
"product_status:fixed": "1980",
"product_status:known_affected": "22",
"product_status:known_not_affected": "42",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: mptcp: fix slab-use-after-free in __inet_lookup_established",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31669.json",
"version": "3"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…