HighFix available
grub — security advisory
A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
- Products
- grub
- Affected versions
- Not specified
- Fixed versions
- 2.06-r0
- CVEs
- CVE-2021-20233
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:02 UTC · Revision 1
Source evidence
A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
osv:ALPINE-CVE-2021-20233
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
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"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-20233",
"method": "structured",
"payload": {
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"summary": "A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.",
"evidence": "osv:ALPINE-CVE-2021-20233",
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"severity": "high",
"structured": {
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"aliases": [
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"metrics": [
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"package": {
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"ecosystem": "Alpine:v3.17"
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"package": {
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"package": {
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"ecosystem": "Alpine:v3.21"
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},
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"package": {
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"ecosystem": "Alpine:v3.23"
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"database_specific": {
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"package": {
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"ecosystem": "Alpine:v3.24"
},
"database_specific": {
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},
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}
],
"modified": "2026-10-23T17:17:56.142296050Z",
"provider": "osv",
"upstream": [
"CVE-2021-20233"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-20233"
]
},
"related_cves": [
{
"value": "CVE-2021-20233",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415282,
"published_at": "2021-03-03T17:15:12.037+00:00"
}