ubuntu-cve-2021-32728
Vulnerability from osv_ubuntu
Published
2021-08-18 16:15
Modified
2026-04-22 07:40
Summary
Details
The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.
Severity
6.5 (Medium)
6.5 (Medium)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "caja-nextcloud",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "dolphin-nextcloud",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "libnextcloudsync0",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nautilus-nextcloud",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nemo-nextcloud",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nextcloud-desktop",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nextcloud-desktop-cmd",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nextcloud-desktop-common",
"binary_version": "2.6.2-1build1"
},
{
"binary_name": "nextcloud-desktop-l10n",
"binary_version": "2.6.2-1build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "nextcloud-desktop",
"purl": "pkg:deb/ubuntu/nextcloud-desktop@2.6.2-1build1?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.5.3-1",
"2.6.0-1",
"2.6.1-1",
"2.6.1-2",
"2.6.2-1",
"2.6.2-1build1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "caja-nextcloud",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "dolphin-nextcloud",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "libnextcloudsync0",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nautilus-nextcloud",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nemo-nextcloud",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nextcloud-desktop",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nextcloud-desktop-cmd",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nextcloud-desktop-common",
"binary_version": "3.4.2-1ubuntu1"
},
{
"binary_name": "nextcloud-desktop-l10n",
"binary_version": "3.4.2-1ubuntu1"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "nextcloud-desktop",
"purl": "pkg:deb/ubuntu/nextcloud-desktop@3.4.2-1ubuntu1?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.2.3-0ubuntu1",
"3.3.5-1",
"3.3.5-1ubuntu1",
"3.4.2-1",
"3.4.2-1ubuntu1"
]
}
],
"aliases": [],
"details": "The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.",
"id": "UBUNTU-CVE-2021-32728",
"modified": "2026-04-22T07:40:03Z",
"published": "2021-08-18T16:15:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2021-32728"
},
{
"type": "REPORT",
"url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5"
},
{
"type": "REPORT",
"url": "https://github.com/nextcloud/desktop/pull/3338"
},
{
"type": "REPORT",
"url": "https://hackerone.com/reports/1189162"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2021-32728"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2021-32728"
]
}
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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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