MediumFix available
samba — security advisory
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
- Products
- samba
- Affected versions
- Not specified
- Fixed versions
- 4.12.15-r0, 4.13.8-r0, 4.14.4-r0
- CVEs
- CVE-2021-20254
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:02 UTC · Revision 1
Source evidence
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
osv:ALPINE-CVE-2021-20254
samba
Fixed versions: 4.12.15-r0
samba
Fixed versions: 4.13.8-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
samba
Fixed versions: 4.14.4-r0
Complete source record
{
"id": "a16010e90471bdaaba90fc55afb8f47229bdff2e38d67e08b49259b81febfb74",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-20254",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-20254",
"summary": "A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.",
"evidence": "osv:ALPINE-CVE-2021-20254",
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"affected_versions": []
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],
"severity": "medium",
"structured": {
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"aliases": [
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"metrics": [
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],
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},
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},
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],
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],
"package": {
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"ecosystem": "Alpine:v3.16"
},
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"package": {
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],
"package": {
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"ecosystem": "Alpine:v3.18"
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"database_specific": {
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],
"package": {
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},
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},
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],
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}
],
"modified": "2026-10-23T17:17:56.143047938Z",
"provider": "osv",
"upstream": [
"CVE-2021-20254"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-20254"
]
},
"related_cves": [
{
"value": "CVE-2021-20254",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415284,
"published_at": "2021-05-05T14:15:07.883+00:00"
}