MediumFix available
grub — security advisory
If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.
- Products
- grub
- Affected versions
- Not specified
- Fixed versions
- 2.06-r0
- CVEs
- CVE-2021-3418
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:05 UTC · Revision 1
Source evidence
If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.
osv:ALPINE-CVE-2021-3418
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
grub
Fixed versions: 2.06-r0
Complete source record
{
"id": "fa5632978272b44d0a11a58213f7612657fa6a3723ffebba3473f598f7829408",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-3418",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-3418",
"summary": "If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.",
"evidence": "osv:ALPINE-CVE-2021-3418",
"products": [
{
"name": {
"value": "grub",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/6/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "grub",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.06-r0",
"evidence": "/affected/7/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "ALPINE-CVE-2021-3418",
"aliases": [
"ALPINE-CVE-2021-3418"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.17"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.18"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.19"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.20"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.21"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.22"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.23"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.06-r0"
}
]
}
],
"package": {
"name": "grub",
"purl": "pkg:apk/alpine/grub?arch=source",
"ecosystem": "Alpine:v3.24"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-3418.json"
},
"ecosystem_specific": {}
}
],
"modified": "2026-10-23T17:17:56.192622650Z",
"provider": "osv",
"upstream": [
"CVE-2021-3418"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-3418"
]
},
"related_cves": [
{
"value": "CVE-2021-3418",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415463,
"published_at": "2021-03-15T22:15:13.907+00:00"
}