---
id: CVE-2026-70637
title: >-
  LightFTP through 2.4 contains multiple data race vulnerabilities in ftpserv.c
  that allow anonymous attackers to cause undefined behavior by issuing LIST
  followed by ABOR commands without authentication
summary: >-
  LightFTP through 2.4 contains multiple data race vulnerabilities in ftpserv.c
  that allow anonymous attackers to cause undefined behavior by issuing LIST
  followed by ABOR commands without authentication. The control thread closes
  data_soc…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-820
published: '2026-08-06'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:43:32.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-70637'
references:
  - url: 'https://github.com/hfiref0x/LightFTP/issues/75'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/lightftp-data-race-condition-via-abor-command-in-ftpserv-c
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00365
epssPercentile: 0.27537
ingestedAt: '2026-09-24T20:51:40.185Z'
---

## Overview

LightFTP through 2.4 contains multiple data race vulnerabilities in ftpserv.c that allow anonymous attackers to cause undefined behavior by issuing LIST followed by ABOR commands without authentication. The control thread closes data_socket and file_fd descriptors while worker threads concurrently operate on the same fields in worker_thread_cleanup, allowing stale file descriptors to be reassigned by the OS and subsequently used by worker threads on unrelated resources, resulting in potential denial of service.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.