Vulnerability in Hfiref0x Lightftp
CVE-2026-67607
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.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
EPSS: 0.003 (22.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Hfiref0x Lightftp — versions 0
Weakness classification (CWE)
References
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-67607?
- CVE-2026-67607 is a medium-severity vulnerability in Hfiref0x Lightftp, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.9/10. Published 2026-07-31.
- How severe is CVE-2026-67607?
- Medium severity. CVSS v3 base score is 5.9 out of 10.