CVE-2026-67607 LightFTP 2.3.1 Race Condition DoS via worker_thread_cleanup
Remote unauthenticated attackers can crash the LightFTP daemon via a race condition in worker thread cleanup, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-67607?
CVE-2026-67607 is a high-severity vulnerability in hfiref0x LightFTP, published on 31 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-367
Which versions are affected by CVE-2026-67607?
How do I fix CVE-2026-67607?
No fix has been published for CVE-2026-67607 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-67607 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67607 exists.
Sources
Also known as GHSA-857x-mm78-cq2m.