Data Race Vulnerabilities in LightFTP Affected by Concurrency Issues
CVE-2026-70637

8.2HIGH

Key Information:

Vendor

Hfiref0x

Status
Lightftp
Vendor
CVE Published:
6 August 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-70637?

LightFTP version 2.4 is susceptible to multiple data race vulnerabilities that arise from concurrent execution paths in the control and worker threads. Specifically, when an anonymous attacker issues the LIST command followed by the ABOR command, the control thread may prematurely close data_socket and file_fd descriptors. This premature closure results in a situation where the worker threads can operate on stale file descriptors, leading to potential undefined behavior and resource mismanagement. Consequently, this exploitation could enable attackers to cause a denial of service, significantly impacting the availability of the affected service.

Affected Version(s)

LightFTP 0 <= 4.0

LightFTP 0 <= 4.0

LightFTP 0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-70637 - Proof of Concept

References

https://github.com/hfiref0x/LightFTP/issues/75
technical-descriptionexploit
https://www.vulncheck.com/advisories/lightftp-data-race-c...
third-party-advisory

CVSS V4

Score:
8.2
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

grant_Y (@grant-yim)
Gjoko Krstic of Zero Science Lab
.