CVE-2021-37533Apache Commons Net's FTP client trusts the host from PASV response by default
- 6.5MediumCVSS base score
- 2.2%Exploitation in 30 daysEPSS · top 17% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By apache
- 17 months later
· 17 months later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
| NVDNVD · Modified | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 2.2% · top 17% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
Apache Software Foundation · Apache Commons Net
- affected Apache Commons Net – < 3.9.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencommons-net:commons-netGHSA-cgp8-4m63-fhh5 (opens in a new tab)
References
References4
- https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 (opens in a new tab)x_transferred
- [oss-security] 20221203 CVE-2021-37533: Apache Commons Net's FTP client trusts the host from PASV response by default (opens in a new tab)mailing-listx_transferred
- [debian-lts-announce] 20221229 [SECURITY] [DLA 3251-1] libcommons-net-java security update (opens in a new tab)mailing-listx_transferred
- DSA-5307 (opens in a new tab)vendor-advisoryx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2022-7599 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-cgp8-4m63-fhh5 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-37533)Record last updated .