Vulnerability-Lookup

CVE-2026-67607 (GCVE-0-2026-67607)

Vulnerability from cvelistv5 – Published: 2026-07-31 15:59 – Updated: 2026-08-03 19:59 X_Open Source

Title

LightFTP 2.3.1 Race Condition DoS via worker_thread_cleanup

Summary

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.

Severity

8.2 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

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

Assigner

VulnCheck

References

2 references

URL	Tags
https://github.com/zeroscience/tuktam#real-world-…	technical-description
https://www.vulncheck.com/advisories/lightftp-rac…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
hfiref0x	LightFTP	Affected: 0 , ≤ 2.3.1 (semver)

Date Public

2026-07-30 00:00

Credits

Gjoko Krstic of Zero Science Lab

Show details on NVD website

JSON

To clipboard

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GHSA-857X-MM78-CQ2M

Vulnerability from github – Published: 2026-07-31 18:32 – Updated: 2026-07-31 18:32

Details

LightFTP 2.3.1 contains a race condition vulnerability that allows remote attackers to crash the server by racing a fresh connection that reuses the FTP context against an in-progress ABRT cleanup. Attackers can exploit the unprotected re-check of WorkerThreadId between worker_thread_cleanup() and pthread_join() outside of MTLock to cause pthread_join() to operate on an invalid thread ID, resulting in a server crash. CVE-2024-11144 identifies an incomplete fix of this vulnerability.

Severity

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

8.2 (High)


                  
                    CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

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  "affected": [],
  "aliases": [
    "CVE-2026-67607"
  ],
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    "cwe_ids": [
      "CWE-367"
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    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-31T16:17:11Z",
    "severity": "HIGH"
  },
  "details": "LightFTP 2.3.1 contains a race condition vulnerability that allows remote attackers to crash the server by racing a fresh connection that reuses the FTP context against an in-progress ABRT cleanup. Attackers can exploit the unprotected re-check of WorkerThreadId between worker_thread_cleanup() and pthread_join() outside of MTLock to cause pthread_join() to operate on an invalid thread ID, resulting in a server crash. CVE-2024-11144 identifies an incomplete fix of this vulnerability.",
  "id": "GHSA-857x-mm78-cq2m",
  "modified": "2026-07-31T18:32:18Z",
  "published": "2026-07-31T18:32:18Z",
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    {
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      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67607"
    },
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      "url": "https://github.com/zeroscience/tuktam#real-world-case-study-lightftp-cve-2024-11144"
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    },
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    }
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-67607 (GCVE-0-2026-67607)

GHSA-857X-MM78-CQ2M

Tags

Sightings

Nomenclature