FKIE_CVE-2021-47010
Vulnerability from fkie_nvd - Published: 2024-02-28 09:15 - Updated: 2026-06-17 04:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: Only allow init netns to set default tcp cong to a restricted algo
tcp_set_default_congestion_control() is netns-safe in that it writes
to &net->ipv4.tcp_congestion_control, but it also sets
ca->flags |= TCP_CONG_NON_RESTRICTED which is not namespaced.
This has the unintended side-effect of changing the global
net.ipv4.tcp_allowed_congestion_control sysctl, despite the fact that it
is read-only: 97684f0970f6 ("net: Make tcp_allowed_congestion_control
readonly in non-init netns")
Resolve this netns "leak" by only allowing the init netns to set the
default algorithm to one that is restricted. This restriction could be
removed if tcp_allowed_congestion_control were namespace-ified in the
future.
This bug was uncovered with
https://github.com/JonathonReinhart/linux-netns-sysctl-verify
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp_cong.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "992de06308d9a9584d59b96d294ac676f924e437",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
},
{
"lessThan": "9884f745108f7d25b189bbcd6754e284fb29ab68",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
},
{
"lessThan": "6c1ea8bee75df8fe2184a50fcd0f70bf82986f42",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
},
{
"lessThan": "efe1532a6e1a8e3c343d04fff510f0ed80328f9c",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
},
{
"lessThan": "e7d7bedd507bb732e600403b7a96f9fe48d0ca31",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
},
{
"lessThan": "8d432592f30fcc34ef5a10aac4887b4897884493",
"status": "affected",
"version": "6670e152447732ba90626f36dfc015a13fbf150e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp_cong.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.15"
},
{
"lessThan": "4.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"version": "4.19.191",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"version": "5.4.119",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.37",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.11.*",
"status": "unaffected",
"version": "5.11.21",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.12.*",
"status": "unaffected",
"version": "5.12.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "5.13",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"cpes": [
"cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "linux_kernel",
"vendor": "linux",
"versions": [
{
"lessThan": "992de06308d9",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"lessThan": "9884f745108f",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"lessThan": "6c1ea8bee75d",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"lessThan": "efe1532a6e1a",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"lessThan": "e7d7bedd507b",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"lessThan": "8d432592f30f",
"status": "affected",
"version": "6670e1524477",
"versionType": "custom"
},
{
"status": "affected",
"version": "4.15"
},
{
"lessThan": "4.15",
"status": "unaffected",
"version": "0",
"versionType": "custom"
},
{
"lessThanOrEqual": "4.20",
"status": "unaffected",
"version": "4.19.191",
"versionType": "custom"
},
{
"lessThanOrEqual": "5.5",
"status": "unaffected",
"version": "5.4.119",
"versionType": "custom"
},
{
"lessThanOrEqual": "5.11",
"status": "unaffected",
"version": "5.10.37",
"versionType": "custom"
},
{
"lessThanOrEqual": "5.12",
"status": "unaffected",
"version": "5.11.21",
"versionType": "custom"
},
{
"lessThanOrEqual": "5.13",
"status": "unaffected",
"version": "5.12.4",
"versionType": "custom"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "5.13",
"versionType": "custom"
}
]
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "5B6E6817-19A8-4C0A-8807-71DA48CF9191",
"versionEndExcluding": "4.19.191",
"versionStartIncluding": "4.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionEndExcluding": "5.12.4",
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: Only allow init netns to set default tcp cong to a restricted algo\n\ntcp_set_default_congestion_control() is netns-safe in that it writes\nto \u0026net-\u003eipv4.tcp_congestion_control, but it also sets\nca-\u003eflags |= TCP_CONG_NON_RESTRICTED which is not namespaced.\nThis has the unintended side-effect of changing the global\nnet.ipv4.tcp_allowed_congestion_control sysctl, despite the fact that it\nis read-only: 97684f0970f6 (\"net: Make tcp_allowed_congestion_control\nreadonly in non-init netns\")\n\nResolve this netns \"leak\" by only allowing the init netns to set the\ndefault algorithm to one that is restricted. This restriction could be\nremoved if tcp_allowed_congestion_control were namespace-ified in the\nfuture.\n\nThis bug was uncovered with\nhttps://github.com/JonathonReinhart/linux-netns-sysctl-verify"
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: solo permite que init netns establezca la cong tcp predeterminada en un algoritmo restringido tcp_set_default_congestion_control() es seguro para netns porque escribe en \u0026amp;net-\u0026gt;ipv4.tcp_congestion_control, pero tambi\u00e9n establece ca-\u0026gt;flags |= TCP_CONG_NON_RESTRICTED que no tiene espacio de nombres. Esto tiene el efecto secundario no deseado de cambiar el sistema global net.ipv4.tcp_allowed_congestion_control, a pesar de que es de solo lectura: 97684f0970f6 (\"net: Make tcp_allowed_congestion_control readonly in non-init netns\") Resuelva esta \"fuga\" de netns solo permite que las redes de inicio establezcan el algoritmo predeterminado en uno restringido. Esta restricci\u00f3n podr\u00eda eliminarse si tcp_allowed_congestion_control tuviera un espacio de nombres en el futuro. Este error se descubri\u00f3 con https://github.com/JonathonReinhart/linux-netns-sysctl-verify"
}
],
"id": "CVE-2021-47010",
"lastModified": "2026-06-17T04:16:10.390",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2021-47010",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-07-25T15:24:31.511356Z",
"version": "2.0.3"
}
}
]
},
"published": "2024-02-28T09:15:38.657",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
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],
"url": "https://git.kernel.org/stable/c/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42"
},
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{
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"tags": [
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},
{
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"url": "https://git.kernel.org/stable/c/efe1532a6e1a8e3c343d04fff510f0ed80328f9c"
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],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-400"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
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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
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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- 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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
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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
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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.
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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.
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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.