Critical
impacket — security advisory
Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.
- Products
- impacket
- Affected versions
- 0.11.0-1, 0.11.0-2, 0.12.0-3, 0.13.0-1, 0.13.0-2, 0.9.12-1, 0.9.15-1, 0.9.15-5, 0.9.20-4, 0.9.20-5, 0.9.22-2, 0.9.24-1
- Fixed versions
- Not specified
- CVEs
- CVE-2021-31800
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 00:34 UTC · Revision 1
Source evidence
Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.
osv:UBUNTU-CVE-2021-31800
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
impacket
Fixed versions: Not specified
Complete source record
{
"id": "a6173d01a478f14bd4e837ecf835d93254792af0330b9c78be6b8e4a9925596c",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2021-31800",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2021-31800",
"summary": "Multiple path traversal vulnerabilities exist in smbserver.py in Impacket through 0.9.22. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.",
"evidence": "osv:UBUNTU-CVE-2021-31800",
"products": [
{
"name": {
"value": "impacket",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.9.12-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "impacket",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.9.15-1",
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}
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{
"name": {
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},
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"affected_versions": [
{
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"evidence": "/affected/2/versions"
},
{
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"evidence": "/affected/2/versions"
},
{
"value": "0.9.20-5",
"evidence": "/affected/2/versions"
}
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{
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{
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}
]
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{
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},
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"affected_versions": [
{
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"evidence": "/affected/4/versions"
},
{
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}
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},
{
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"prerequisites": [],
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{
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"evidence": "/affected/6/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
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"evidence": "/affected/6/versions"
}
]
},
{
"name": {
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"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
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"evidence": "/affected/7/versions"
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{
"value": "0.13.0-1",
"evidence": "/affected/7/versions"
},
{
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}
]
}
],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2021-31800",
"aliases": [
"UBUNTU-CVE-2021-31800"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=xenial",
"ecosystem": "Ubuntu:16.04:LTS"
},
"versions": [
"0.9.12-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python-impacket",
"binary_version": "0.9.12-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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],
"package": {
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"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"0.9.15-1"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
"binary_name": "python-impacket",
"binary_version": "0.9.15-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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}
]
}
],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"0.9.15-5",
"0.9.20-4",
"0.9.20-5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-impacket",
"binary_version": "0.9.20-5"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"0.9.22-2",
"0.9.24-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-impacket",
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}
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},
{
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],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"0.11.0-1",
"0.11.0-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
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{
"binary_name": "python3-impacket",
"binary_version": "0.11.0-2"
}
]
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},
{
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],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"0.12.0-3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
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{
"binary_name": "python3-impacket",
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}
]
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{
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],
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"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"0.13.0-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-impacket",
"binary_version": "0.13.0-2"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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}
]
}
],
"package": {
"name": "impacket",
"purl": "pkg:deb/ubuntu/impacket?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"0.12.0-3",
"0.13.0-1",
"0.13.0-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-31800.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-impacket",
"binary_version": "0.13.0-2"
}
]
}
}
],
"modified": "2026-10-17T12:55:46.337240963Z",
"provider": "osv",
"upstream": [
"CVE-2021-31800"
],
"references": [
"https://ubuntu.com/security/CVE-2021-31800",
"https://github.com/SecureAuthCorp/impacket/commit/49c643bf66620646884ed141c94e5fdd85bcdd2f",
"https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L2008",
"https://github.com/SecureAuthCorp/impacket/releases",
"https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L876",
"https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L2958",
"https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L3485",
"https://www.cve.org/CVERecord?id=CVE-2021-31800"
]
},
"related_cves": [
{
"value": "CVE-2021-31800",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 354048,
"published_at": "2021-05-05T11:15:00+00:00"
}