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GHSA-jw37-5gqr-cf9j

CriticalCVSS 9.1 / 10
Published Aug 17, 2020·Last modified Mar 13, 2026
Affected Components(0)

No affected components available

Description

Background

The FTP protocol creates two connections, one for commands and one for transferring data. This second data connection can be created in two ways, on the server by sending the PASV command, or on the client by sending the PORT command.

The PORT command sends the IP and port for the server to connect to the client with.

Issue

Since the client can send an arbitrary IP with the PORT command, this can be used to cause the server to make a connection elsewhere.

Patches

  • fix: disallow PORT connections to alternate hosts: e449e75219d918c400dec65b4b0759f60476abca

Deprecation notices have been published for older versions.

Workarounds

Blacklisting the FTP Command PORT will prevent the server from exposing this behaviour through active connections until a fix is applied.

const ftp = new FtpSrv({
  blacklist: ['PORT']
});

References

https://www.npmjs.com/advisories/1445

Credits

Thank you to; @trs for fixing it @andreeleuterio for reporting it to us for an anonymous user (Vincent) through the NPM platform @quiquelhappy for bringing it to our attention after it slipped through the cracks during Christmas

For more information

If you have any questions or comments about this advisory:

Risk Scores
Base Score
9.1

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.

Threat Intelligence
8.3

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
1.86%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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