Vulnerability · Published Jul 31, 2026 · Assigned by VulnCheck

CVE-2026-67607LightFTP 2.3.1 Race Condition DoS via worker_thread_cleanup

Medium 5.9

In plain English

A medium-severity security flaw in LightFTP from hfiref0x. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.4%top 66.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

LightFTP 2.3.1 contains a residual race condition vulnerability (an incomplete fix for CVE-2024-11144) in the worker_thread_cleanup() function of ftpserv.c that allows remote unauthenticated attackers to destabilize or crash the daemon by triggering unsynchronized access to shared per-connection state without holding the required mutex lock. Attackers can send a data-transfer command such as LIST followed immediately by ABOR to exploit the missing synchronization on shared context and detached thread id reuse, resulting in daemon destabilization or crash which can lead to a denial of service. The 2.3.1 patch only narrowed the timing window (an extra re-check and reordered cleanup), it never added the missing lock, so the underlying race remains.

Affected products (as reported)

Vendor	Product	Versions
hfiref0x	LightFTP	0 – through 2.3.1

Weakness: CWE-367 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Researcher Disclosure technical-description
https://www.vulncheck.com/advisories/lightftp-race-condition-dos-via-worker-thread-cleanup third-party-advisory