libcommons-net-java — security advisory
Prior to Apache Commons Net 3.9.0, Net's FTP client trusts the host from PASV response by default. A malicious server can redirect the Commons Net code to use a different host, but the user has to connect to the malicious server in the first place. This may lead to leakage of information about services running on the private network of the client. The default in version 3.9.0 is now false to ignore such hosts, as cURL does. See https://issues.apache.org/jira/browse/NET-711.
- Products
- libcommons-net-java
- Affected versions
- Not specified
- Fixed versions
- 3.9.0-1
- CVEs
- CVE-2021-37533
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 00:50 UTC · Revision 1
Source evidence
Prior to Apache Commons Net 3.9.0, Net's FTP client trusts the host from PASV response by default. A malicious server can redirect the Commons Net code to use a different host, but the user has to connect to the malicious server in the first place. This may lead to leakage of information about services running on the private network of the client. The default in version 3.9.0 is now false to ignore such hosts, as cURL does. See https://issues.apache.org/jira/browse/NET-711.
osv:DEBIAN-CVE-2021-37533
libcommons-net-java
Fixed versions: 3.9.0-1
libcommons-net-java
Fixed versions: 3.9.0-1
libcommons-net-java
Fixed versions: 3.9.0-1
Complete source record
{
"id": "a66b768cb00227efafd5da6eff94ed23a1032ad85a5111ffbb19180b585a8510",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-37533",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-37533",
"summary": "Prior to Apache Commons Net 3.9.0, Net's FTP client trusts the host from PASV response by default. A malicious server can redirect the Commons Net code to use a different host, but the user has to connect to the malicious server in the first place. This may lead to leakage of information about services running on the private network of the client. The default in version 3.9.0 is now false to ignore such hosts, as cURL does. See https://issues.apache.org/jira/browse/NET-711.",
"evidence": "osv:DEBIAN-CVE-2021-37533",
"products": [
{
"name": {
"value": "libcommons-net-java",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.9.0-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libcommons-net-java",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.9.0-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libcommons-net-java",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.9.0-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2021-37533",
"aliases": [
"DEBIAN-CVE-2021-37533"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.9.0-1"
}
]
}
],
"package": {
"name": "libcommons-net-java",
"purl": "pkg:deb/debian/libcommons-net-java?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-37533.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.9.0-1"
}
]
}
],
"package": {
"name": "libcommons-net-java",
"purl": "pkg:deb/debian/libcommons-net-java?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-37533.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.9.0-1"
}
]
}
],
"package": {
"name": "libcommons-net-java",
"purl": "pkg:deb/debian/libcommons-net-java?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-37533.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:03:50.699779865Z",
"provider": "osv",
"upstream": [
"CVE-2021-37533"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-37533"
]
},
"related_cves": [
{
"value": "CVE-2021-37533",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 422439,
"published_at": "2022-12-03T15:15:09.747+00:00"
}