CVE-2021-47294 (GCVE-0-2021-47294)
Vulnerability from cvelistv5 – Published: 2024-05-21 14:35 – Updated: 2026-05-23 15:19
VLAI
EPSS
VEX
Title
netrom: Decrease sock refcount when sock timers expire
Summary
In the Linux kernel, the following vulnerability has been resolved:
netrom: Decrease sock refcount when sock timers expire
Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use
sock timer API. It replaces mod_timer() by sk_reset_timer(), and
del_timer() by sk_stop_timer().
Function sk_reset_timer() will increase the refcount of sock if it is
called on an inactive timer, hence, in case the timer expires, we need to
decrease the refcount ourselves in the handler, otherwise, the sock
refcount will be unbalanced and the sock will never be freed.
Severity
No CVSS data available.
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-28 19:24 UTC
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
ce29e8a259de767f7210d346ad2b031cb8ab2732 , < 853262355518cd1247515b74e83fabf038aa6c29
(git)
Affected: baa9e32336bf6d0d74a7c3486d2a27feaf57cd5f , < a01634bf91f2b6c42583770eb6815fb6d1e251cf (git) Affected: 0adf571fa34b27bd0b97b408cc0f0dc54b72f0eb , < 48866fd5c361ea417ed24b43fc2a7dc2f5b060ef (git) Affected: 2c6b572458a9127e8070df13fa7f115c29ab1d92 , < 9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 (git) Affected: 63346650c1a94a92be61a57416ac88c0a47c4327 , < 25df44e90ff5959b5c24ad361b648504a7e39ef3 (git) Affected: 63346650c1a94a92be61a57416ac88c0a47c4327 , < 6811744bd0efb9e472cb15d066cdb460beb8cb8a (git) Affected: 63346650c1a94a92be61a57416ac88c0a47c4327 , < bc1660206c3723c37ed4d622ad81781f1e987250 (git) Affected: 63346650c1a94a92be61a57416ac88c0a47c4327 , < 517a16b1a88bdb6b530f48d5d153478b2552d9a8 (git) Affected: f1d9a1f2ef6ff17293d21d5e6b80e04bea0cf508 (git) Affected: 519e8a22a454b1f1baa3a151b184fe51bc18e178 (git) Affected: 4.4.173 , < 4.4.277 (semver) Affected: 4.9.155 , < 4.9.277 (semver) Affected: 4.14.98 , < 4.14.241 (semver) Affected: 4.19.20 , < 4.19.199 (semver) Affected: 3.18.134 , < 3.19 (semver) Affected: 4.20.7 , < 4.21 (semver) |
guessed | |
| Linux | Linux |
Affected:
5.0
Unaffected: 0 , < 5.0 (semver) Unaffected: 4.4.277 , ≤ 4.4.* (semver) Unaffected: 4.9.277 , ≤ 4.9.* (semver) Unaffected: 4.14.241 , ≤ 4.14.* (semver) Unaffected: 4.19.199 , ≤ 4.19.* (semver) Unaffected: 5.4.136 , ≤ 5.4.* (semver) Unaffected: 5.10.54 , ≤ 5.10.* (semver) Unaffected: 5.13.6 , ≤ 5.13.* (semver) Unaffected: 5.14 , ≤ * (original_commit_for_fix) |
guessed |
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"versionStartIncluding": "4.14.98",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "4.19.199",
"versionStartIncluding": "4.19.20",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.4.136",
"versionStartIncluding": "5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.54",
"versionStartIncluding": "5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.13.6",
"versionStartIncluding": "5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.14",
"versionStartIncluding": "5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.18.134",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.20.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetrom: Decrease sock refcount when sock timers expire\n\nCommit 63346650c1a9 (\"netrom: switch to sock timer API\") switched to use\nsock timer API. It replaces mod_timer() by sk_reset_timer(), and\ndel_timer() by sk_stop_timer().\n\nFunction sk_reset_timer() will increase the refcount of sock if it is\ncalled on an inactive timer, hence, in case the timer expires, we need to\ndecrease the refcount ourselves in the handler, otherwise, the sock\nrefcount will be unbalanced and the sock will never be freed."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-23T15:19:39.451Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29"
},
{
"url": "https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf"
},
{
"url": "https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef"
},
{
"url": "https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950"
},
{
"url": "https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3"
},
{
"url": "https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a"
},
{
"url": "https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250"
},
{
"url": "https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8"
}
],
"title": "netrom: Decrease sock refcount when sock timers expire",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2021-47294",
"datePublished": "2024-05-21T14:35:18.034Z",
"dateReserved": "2024-05-21T13:27:52.130Z",
"dateUpdated": "2026-05-23T15:19:39.451Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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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.
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.
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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.
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