CVE-2021-37533
Apache Commons Net's FTP client trusts the host from PASV response by default
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.
INFO
Published Date :
Dec. 3, 2022, 3:15 p.m.
Last Modified :
April 24, 2025, 4:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source | 
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | 
Solution
- Upgrade Apache Commons Net to version 3.9.0 or later.
 - Update the affected libcommons-net-java package.
 
References to Advisories, Solutions, and Tools
                                            Here, you will find a curated list of external links that provide in-depth
                                            information, practical solutions, and valuable tools related to
                                            CVE-2021-37533.
                                        
| URL | Resource | 
|---|---|
| http://www.openwall.com/lists/oss-security/2022/12/03/1 | Issue Tracking Mailing List Third Party Advisory | 
| https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 | Issue Tracking Mailing List Vendor Advisory | 
| https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html | Mailing List Third Party Advisory | 
| https://www.debian.org/security/2022/dsa-5307 | Third Party Advisory | 
| http://www.openwall.com/lists/oss-security/2022/12/03/1 | Issue Tracking Mailing List Third Party Advisory | 
| https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 | Issue Tracking Mailing List Vendor Advisory | 
| https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html | Mailing List Third Party Advisory | 
| https://www.debian.org/security/2022/dsa-5307 | Third Party Advisory | 
CWE - Common Weakness Enumeration
            While CVE identifies
            specific instances of vulnerabilities, CWE categorizes the common flaws or
            weaknesses that can lead to vulnerabilities. CVE-2021-37533 is
            associated with the following CWEs:
        
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
            (CAPEC)
            stores attack patterns, which are descriptions of the common attributes and
            approaches employed by adversaries to exploit the CVE-2021-37533
            weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
			The following list is the news that have been mention
			CVE-2021-37533 vulnerability anywhere in the article.
		
                The following table lists the changes that have been made to the
                CVE-2021-37533 vulnerability over time.
            
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
- 
                            
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 24, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N  - 
                            
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2022/12/03/1 Added Reference https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 Added Reference https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html Added Reference https://www.debian.org/security/2022/dsa-5307  - 
                            
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value  - 
                            
Modified Analysis by [email protected]
Jan. 10, 2023
Action Type Old Value New Value Changed Reference Type https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html No Types Assigned https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html Mailing List, Third Party Advisory Changed Reference Type https://www.debian.org/security/2022/dsa-5307 No Types Assigned https://www.debian.org/security/2022/dsa-5307 Third Party Advisory Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*  - 
                            
CVE Modified by [email protected]
Dec. 30, 2022
Action Type Old Value New Value Added Reference https://www.debian.org/security/2022/dsa-5307 [No Types Assigned]  - 
                            
CVE Modified by [email protected]
Dec. 29, 2022
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2022/12/msg00038.html [No Types Assigned]  - 
                            
Initial Analysis by [email protected]
Dec. 06, 2022
Action Type Old Value New Value Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Changed Reference Type http://www.openwall.com/lists/oss-security/2022/12/03/1 No Types Assigned http://www.openwall.com/lists/oss-security/2022/12/03/1 Issue Tracking, Mailing List, Third Party Advisory Changed Reference Type https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 No Types Assigned https://lists.apache.org/thread/o6yn9r9x6s94v97264hmgol1sf48mvx7 Issue Tracking, Mailing List, Vendor Advisory Added CPE Configuration OR *cpe:2.3:a:apache:commons_net:*:*:*:*:*:*:*:* versions up to (excluding) 3.9.0  - 
                            
CVE Modified by [email protected]
Dec. 03, 2022
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2022/12/03/1 [No Types Assigned]  - 
                            
CVE Modified by [email protected]
Dec. 03, 2022
Action Type Old Value New Value Changed 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. 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.  
Vulnerability Scoring Details
Base CVSS Score: 6.5
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.19 }} 0.01%
score
0.41226
percentile