# CVE-2026-102990: basic-ftp: Quadratic-time CPU denial of service in Client.list() Unix directory-listing parser (RE_LINE backtracking)

> A malicious FTP server can cause a Node.js application using basic-ftp to hang via quadratic CPU time in directory listing parsing.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** CLSA-2026-1792170033, CLSA-2026-1792170040, DEBIAN-CVE-2026-102990, ECHO-aca6-d26b-eefc, GHSA-c475-qrg2-pj4r, MINI-2h68-vvpj-gxfv, MINI-4fwg-4wqq-m78g, MINI-5jhf-98hq-6ghf, MINI-5r6w-2hr6-2rpc, MINI-6f44-4frh-8m5m, MINI-6rx8-c4f7-wvpx, MINI-83w4-556r-j4j8, MINI-95gj-cwr8-jvw4, MINI-9w72-fp5j-67f4, MINI-c7rh-fq28-mfcq, MINI-ff42-ch67-8mxq, MINI-hqqp-pjhr-66pr, MINI-prgf-p4hm-hwm4, MINI-q5wj-jh7j-rg6x, MINI-qhp4-r78x-3qjf, MINI-v6r6-wwv6-v535, MINI-vfjq-fg96-rcpw, MINI-w7q7-fh6h-4w25, ROOT-APP-NPM-CVE-2026-102990, UBUNTU-CVE-2026-102990

## What is CVE-2026-102990?

CVE-2026-102990 is a high-severity denial of service vulnerability in patrickjuchli basic-ftp, published on 30 Sep 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 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-102990?

2 open source packages ship an affected version, including basic-ftp.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `basic-ftp` | npm | All versions | 6.2.1 |
| `basic-ftp` | npm | All versions | 6.2.1 |

## How do I fix CVE-2026-102990?

Upgrade basic-ftp to 6.2.1 or later.

## Is CVE-2026-102990 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102990 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102990 and fix it if it is affected.

What it is: CVE-2026-102990 is a high-severity denial of service vulnerability in patrickjuchli basic-ftp, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102990 exists.

Affected packages and fixed versions:
- basic-ftp (npm): affected all versions; fixed in 6.2.1
- basic-ftp (npm): affected all versions; fixed in 6.2.1

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.
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-2026-102990/ (Markdown: https://insights.sbomify.com/CVE-2026-102990/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102990
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102990
- OSV: https://osv.dev/vulnerability/CVE-2026-102990

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102990/
Summaries are generated and may contain mistakes; the official description above is the record.