CVE-2026-126346 (CVSS 5.9)

Description

basic-ftp is an FTP client for Node.js. Prior to 6.2.3, FTPContext.send() throws when a command contains carriage return, line feed, or NUL characters, but calls made from response handlers execute synchronously inside the control socket's data event without an exception boundary. In Client.login(), an attacker-influenced password reaches the PASS command after a server sends a 331 response, and in a resumed download an attacker-influenced remote path reaches the RETR command after a 350 response to REST. The resulting exception does not reject client.access() or downloadTo(), escapes ordinary promise error handling, and terminates the Node.js process, while the validation guard still prevents command injection. This issue is fixed in version 6.2.3.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-248 CWE-248

CWE-755 CWE-755

References

Other References

https://github.com/patrickjuchli/basic-ftp/commit/0495b906bdf891e68806721b07b333dba65ec88e https://github.com/patrickjuchli/basic-ftp/releases/tag/v6.2.3 https://github.com/patrickjuchli/basic-ftp/security/advisories/GHSA-r4jh-29pc-gfqr

Frequently Asked Questions

What is CVE-2026-126346? +

basic-ftp is an FTP client for Node.js. Prior to 6.2.3, FTPContext.send() throws when a command contains carriage return, line feed, or NUL characters, but calls made from response handlers execute synchronously inside the control socket's data event without an exception boundary. In Client.login(), an attacker-influenced password reaches the PASS command after a server sends a 331 response, and in a resumed download an attacker-influenced remote path reaches the RETR command after a 350 response to REST. The resulting exception does not reject client.access() or downloadTo(), escapes ordinary promise error handling, and terminates the Node.js process, while the validation guard still prevents command injection. This issue is fixed in version 6.2.3. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-126346? +

CVE-2026-126346 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-126346? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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