ubuntu-cve-2020-27749
Vulnerability from osv_ubuntu
Published
2021-03-02 18:00
Modified
2025-09-08 16:46
Summary
Details
A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Severity
7.5 (High)
6.7 (Medium)
N/A (UNKNOWN)
References
| URL | Type | |
|---|---|---|
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "grub-efi-amd64-signed",
"binary_version": "1.34.24+2.02~beta2-9ubuntu1.21"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:14.04:LTS",
"name": "grub2-signed",
"purl": "pkg:deb/ubuntu/grub2-signed@1.34.24?arch=source\u0026distro=esm-infra-legacy/trusty"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.22",
"1.23",
"1.24",
"1.25",
"1.26",
"1.27",
"1.30",
"1.31",
"1.32",
"1.33",
"1.34",
"1.34.1",
"1.34.2",
"1.34.3",
"1.34.4",
"1.34.5",
"1.34.6",
"1.34.7",
"1.34.8",
"1.34.9",
"1.34.13",
"1.34.14",
"1.34.16",
"1.34.17",
"1.34.18",
"1.34.20",
"1.34.22",
"1.34.24"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "grub-efi-amd64-signed",
"binary_version": "1.167~18.04.5+2.04-1ubuntu44.1.2"
},
{
"binary_name": "grub-efi-arm64-signed",
"binary_version": "1.167~18.04.5+2.04-1ubuntu44.1.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "grub2-signed",
"purl": "pkg:deb/ubuntu/grub2-signed@1.167~18.04.5?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.167~18.04.5"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.85",
"1.86",
"1.87",
"1.89",
"1.91",
"1.92",
"1.93",
"1.93.1",
"1.93.2",
"1.93.3",
"1.93.4",
"1.93.5",
"1.93.7",
"1.93.8",
"1.93.10",
"1.93.11",
"1.93.13",
"1.93.14",
"1.93.15",
"1.93.16",
"1.93.18",
"1.93.19",
"1.93.20",
"1.93.21",
"1.93.22",
"1.93.24",
"1.167~18.04.1",
"1.167~18.04.3"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "grub-efi-amd64",
"binary_version": "2.04-1ubuntu44.1.2"
},
{
"binary_name": "grub-efi-amd64-bin",
"binary_version": "2.04-1ubuntu44.1.2"
},
{
"binary_name": "grub-efi-arm64",
"binary_version": "2.04-1ubuntu44.1.2"
},
{
"binary_name": "grub-efi-arm64-bin",
"binary_version": "2.04-1ubuntu44.1.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "grub2-unsigned",
"purl": "pkg:deb/ubuntu/grub2-unsigned@2.04-1ubuntu44.1.2?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.04-1ubuntu44.1.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.04-1ubuntu44",
"2.04-1ubuntu44.1"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "grub-efi-amd64-signed",
"binary_version": "1.167.2+2.04-1ubuntu44.2"
},
{
"binary_name": "grub-efi-arm64-signed",
"binary_version": "1.167.2+2.04-1ubuntu44.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "grub2-signed",
"purl": "pkg:deb/ubuntu/grub2-signed@1.167.2?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.167.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.128",
"1.129",
"1.130",
"1.131",
"1.133",
"1.134",
"1.135",
"1.136",
"1.137",
"1.138",
"1.139",
"1.140",
"1.141",
"1.142",
"1.142.1",
"1.142.3",
"1.142.4",
"1.142.5",
"1.142.6",
"1.142.8",
"1.142.9",
"1.142.10",
"1.142.11",
"1.167"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "grub-efi-amd64",
"binary_version": "2.04-1ubuntu44.2"
},
{
"binary_name": "grub-efi-amd64-bin",
"binary_version": "2.04-1ubuntu44.2"
},
{
"binary_name": "grub-efi-arm64",
"binary_version": "2.04-1ubuntu44.2"
},
{
"binary_name": "grub-efi-arm64-bin",
"binary_version": "2.04-1ubuntu44.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "grub2-unsigned",
"purl": "pkg:deb/ubuntu/grub2-unsigned@2.04-1ubuntu44.2?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.04-1ubuntu44.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.04-1ubuntu44"
]
}
],
"aliases": [],
"details": "A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.",
"id": "UBUNTU-CVE-2020-27749",
"modified": "2025-09-08T16:46:27Z",
"published": "2021-03-02T18:00:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2020-27749"
},
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-4992-1"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2020-27749"
}
],
"related": [
"USN-4992-1"
],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2020-27749"
]
}
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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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