{"cve":"CVE-2021-37533","nvd":{"published":"2022-12-03T15:15:09.747","modified":"2026-06-17T04:00:41.540","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","score":6.5},"cwes":["CWE-20"],"references":["http://www.openwall.com/lists/oss-security/2022/12/03/1","https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7","https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html","https://www.debian.org/security/2022/dsa-5307","http://www.openwall.com/lists/oss-security/2022/12/03/1"],"products":["apache:commons_net","debian:debian_linux"],"source":"nvd","synced_at":"2026-10-19T21:37:28.463369388+00:00"},"epss":{"cve":"CVE-2021-37533","score":0.02129,"percentile":0.81949,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-cgp8-4m63-fhh5","url":"https://osv.dev/vulnerability/GHSA-cgp8-4m63-fhh5","summary":"Apache Commons Net vulnerable to information leakage via malicious server","modified":"2026-09-10T03:49:47.609594222Z","packages":[{"ecosystem":"Maven","name":"commons-net:commons-net","purl":"pkg:maven/commons-net/commons-net","ranges":["<3.9.0"],"fixed":["3.9.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}