CVE-2026-67607Public exploitNetwork attack vector

Unauthenticated daemon crash via cleanup race

Published Jul 31, 2026 · Updated Jul 31, 2026

TOCTOU race in worker_thread_cleanup in hfiref0x LightFTP 2.3.1 and earlier allows remote attackers to crash the FTP daemon. The function checks shared worker-thread state and later calls pthread_join without holding MTLock, allowing a concurrent connection to replace the thread ID. A LIST command followed immediately by ABOR reaches the race without authentication, and successful timing interrupts the entire FTP service.

CVSS severity8.2
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOCTOU race in worker_thread_cleanup in hfiref0x LightFTP 2.3.1 and earlier allows remote attackers to crash the FTP daemon. The function checks shared worker-thread state and later calls pthread_join without holding MTLock, allowing a concurrent connection to replace the thread ID. A LIST command followed immediately by ABOR reaches the race without authentication, and successful timing interrupts the entire FTP service.

The record

CVE
CVE-2026-67607
Published
Jul 31, 2026
Updated
Jul 31, 2026
Vendor
LightFTP
Product
LightFTP
Classifications
CWE-367, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LightFTP · LightFTPversion=0 <=2.3.1

Published CVSS scores

8.2VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.9VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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