CVE-2026-64422 (GCVE-0-2026-64422)
Vulnerability from cvelistv5 – Published: 2026-07-25 08:51 – Updated: 2026-07-25 08:51
VLAI
EPSS
VEX
Title
net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes
Reject invalid `net.ipv4.tcp_reordering` values before they reach TCP
socket state. The sysctl is stored as an `int` but copied into the
`u32` `tp->reordering` field for new sockets, so negative writes wrap
to large values.
With `tcp_mtu_probing=2`, the wrapped value can overflow the
`tcp_mtu_probe()` size calculation and drive the MTU probing path into
an out-of-bounds read. Route `tcp_reordering` writes through
`proc_dointvec_minmax()` and require it to be at least 1. Also require
`tcp_max_reordering` to be at least 1 so the configured maximum cannot
become negative either.
When registering the table for a non-init network namespace, relocate
`extra2` pointers that refer into `init_net.ipv4` so the
`tcp_reordering` upper bound follows that namespace's
`tcp_max_reordering`.
Harden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.
This keeps the send queue and window checks from being bypassed through
signed integer overflow.
Severity
No CVSS data available.
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < f0d88a4cd03affff6c08adf6c63964e235aede43
(git)
Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < 27ddf4486c7dbf5bdd393fa8bef6b67179796d98 (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < e81f805824a8109504fce090641b17d135b48cd1 (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < 99206ce2244f8a3ed64298d0667c9055845a5dc7 (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < bbae351c0f32f7c200249e4aa6561b2b419dcf69 (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < a094ac95d3b69adfa1676eb9c8eae6835d4f1671 (git) Affected: 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf , < efb8763d7bbb40cff4cc55a6b62c3095a038149c (git) |
|
| Linux | Linux |
Affected:
2.6.24
Unaffected: 0 , < 2.6.24 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix) |
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"version": "0",
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},
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},
{
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"status": "unaffected",
"version": "5.15.212",
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},
{
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{
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"versionType": "semver"
},
{
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"version": "6.12.96",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: bound TCP reordering sysctl writes and MTU probe sizes\n\nReject invalid `net.ipv4.tcp_reordering` values before they reach TCP\nsocket state. The sysctl is stored as an `int` but copied into the\n`u32` `tp-\u003ereordering` field for new sockets, so negative writes wrap\nto large values.\n\nWith `tcp_mtu_probing=2`, the wrapped value can overflow the\n`tcp_mtu_probe()` size calculation and drive the MTU probing path into\nan out-of-bounds read. Route `tcp_reordering` writes through\n`proc_dointvec_minmax()` and require it to be at least 1. Also require\n`tcp_max_reordering` to be at least 1 so the configured maximum cannot\nbecome negative either.\n\nWhen registering the table for a non-init network namespace, relocate\n`extra2` pointers that refer into `init_net.ipv4` so the\n`tcp_reordering` upper bound follows that namespace\u0027s\n`tcp_max_reordering`.\n\nHarden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.\nThis keeps the send queue and window checks from being bypassed through\nsigned integer overflow."
}
],
"providerMetadata": {
"dateUpdated": "2026-07-25T08:51:00.671Z",
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"url": "https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43"
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"url": "https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98"
},
{
"url": "https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae"
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"url": "https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1"
},
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"url": "https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7"
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"url": "https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69"
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"url": "https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671"
},
{
"url": "https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c"
}
],
"title": "net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes",
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"cveId": "CVE-2026-64422",
"datePublished": "2026-07-25T08:51:00.671Z",
"dateReserved": "2026-07-19T15:36:31.787Z",
"dateUpdated": "2026-07-25T08:51:00.671Z",
"state": "PUBLISHED"
},
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"dataVersion": "5.2",
"vulnerability-lookup:meta": {
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"cve": "CVE-2026-64422",
"date": "2026-07-26",
"epss": "0.00185",
"percentile": "0.0841"
},
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"suse_vex": {
"aggregate_severity": "not set",
"current_release_date": "2026-07-25T15:59:38Z",
"cve": "CVE-2026-64422",
"id": "CVE-2026-64422",
"initial_release_date": "2026-07-25T15:59:38Z",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-64422",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64422.json",
"version": "2"
}
}
}
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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.
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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.
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