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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-37533

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
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-37533
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 05:04 UTC · Revision 1

Source evidence

CVE-2021-37533

core-osv · Original source

Published 3 Dec 2022, 15:15 UTC

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:CVE-2021-37533
Complete source record
{
  "id": "ec36f31976f15ac19de49b0335086e4c061bed69323cae051764e68a7698e470",
  "url": "https://osv.dev/vulnerability/CVE-2021-37533",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "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:CVE-2021-37533",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-37533",
      "aliases": [
        "CVE-2021-37533",
        "GHSA-cgp8-4m63-fhh5"
      ],
      "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": [
            {
              "repo": "https://github.com/apache/commons-net",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1595ad2cbb5b7d7e055613c1a76a3a4c82318aee"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:apache:commons_net:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.9.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "rel/commons-net-3.8.0",
            "commons-net-3.8.0-RC1",
            "rel/commons-net-3.7.2",
            "commons-net-3.7.2-RC1",
            "rel/commons-net-3.7.1",
            "commons-net-3.7.1-RC2",
            "commons-net-3.7.1-RC1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-37533.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:24.246439472Z",
      "provider": "osv",
      "references": [
        "https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html",
        "https://www.debian.org/security/2022/dsa-5307",
        "https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "10.0"
                  },
                  {
                    "last_affected": "10.0"
                  },
                  {
                    "introduced": "11.0"
                  },
                  {
                    "last_affected": "11.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-37533",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 431103,
  "published_at": "2022-12-03T15:15:09.747+00:00"
}