basic-ftp: Incomplete CRLF Injection Protection Allows Arbitrary FTP Command Execution via Credentials and MKD Commands

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary basic-ftp's CRLF injection protection (added in commit 2ecc8e2 for GHSA-chqc-8p9q-pq6q) is incomplete. Two code paths bypass the protectWhitespace() control character check: (1) the login() method directly concatenates user-supplied credentials into USER/PASS FTP commands without any validation, and (2) the openDir() method sends an MKD command before cd() invokes protectWhitespace(), creating a TOCTOU bypass. Both vectors allow an attacker who controls input to inject arbitrary FTP commands into the control connection. Details Vector 1: Credential Injection (login) The login() method constructs FTP commands by direct string concatenation with no CRLF validation: FtpContext.send() writes directly to the TCP socket: The protectWhitespace() method (line 762) rejects \r, \n, and \0 characters — but it is only called for path-based operations. Credentials never pass through it. The public access() method (line 268) passes options.user and options.password directly to login() with…

Published by the source

10 Apr 2026, 20:18 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:48 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6v7q-wjvx-w8wg

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6v7q-wjvx-w8wg

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-6v7q-wjvx-w8wg

Advisory: basic-ftp: Incomplete CRLF Injection Protection Allows Arbitrary FTP Command Execution via Credentials and MKD Commands
IDs: GHSA-6v7q-wjvx-w8wg
Record: https://patchnext.com/advisories/ghsa-6v7q-wjvx-w8wg (revision 2, source checked 26 Oct 2026, 12:48 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: basic-ftp 5.2.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm basic-ftp: affected <= 5.2.1; fixed in 5.2.2

## Suggested inspection (read-only)
- `npm ls basic-ftp --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on basic-ftp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6v7q-wjvx-w8wg (OSV record GHSA-6v7q-wjvx-w8wg lists affected ranges: npm basic-ftp >=0 <5.2.2 (fixed))
- Verified: https://github.com/advisories/GHSA-6v7q-wjvx-w8wg (GitHub-reviewed advisory GHSA-6v7q-wjvx-w8wg lists affected ranges: npm basic-ftp >=0 <=5.2.1)

Commands are suggestions: review each one before running it.