# CVE-2026-126346: basic-ftp: Uncaught exception crashes the Node.js process when a password (or resumed-download path) contains CR/LF

> Attacker-influenced passwords or download paths with CR/LF crash Node.js processes using basic-ftp; apps passing untrusted input to it should care.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** Yes (`FTPContext.send()`, `Client.login()`, `downloadTo()`)
- **Fix available:** Yes
- **Published:** 12 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-r4jh-29pc-gfqr

## What is CVE-2026-126346?

CVE-2026-126346 is a medium-severity denial of service vulnerability in patrickjuchli basic-ftp, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions), CWE-248 (Uncaught Exception)

## Which versions are affected by CVE-2026-126346?

1 open source package ship an affected version, including basic-ftp.

An affected version is only exploitable if your software calls FTPContext.send(), Client.login() or downloadTo(). Many projects that include it are not exposed.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `basic-ftp` | npm | All versions | 6.2.3 |

## How do I fix CVE-2026-126346?

Upgrade basic-ftp to 6.2.3 or later.

## Is CVE-2026-126346 being exploited?

There is no known exploitation of CVE-2026-126346 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-126346 and fix it if it is affected.

What it is: CVE-2026-126346 is a medium-severity denial of service vulnerability in patrickjuchli basic-ftp, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-126346 in the wild and no public exploit code.
Exposure: An affected version is only exploitable if your software calls FTPContext.send(), Client.login() or downloadTo(). Many projects that include it are not exposed.

Affected packages and fixed versions:
- basic-ftp (npm): affected all versions; fixed in 6.2.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
   If an affected version is present, also search the code for calls to FTPContext.send(), Client.login() or downloadTo() and report whether any exist.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-126346/ (Markdown: https://insights.sbomify.com/CVE-2026-126346/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-126346
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126346
- OSV: https://osv.dev/vulnerability/CVE-2026-126346

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-126346/
Summaries are generated and may contain mistakes; the official description above is the record.