ProFTPD 1.3.7a contains a denial of service vulnerability that allows attackers to overwhelm the server by creating multiple simultaneous FTP connections. Attackers can repeatedly establish connections using threading to exhaust server connection limits and block legitimate user access.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00041.

Exploitation poc

Automatable yes

Technical Impact partial

Affected Vendors & Products

No data.

No data.

No data.

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
http://www.proftpd.org/ cve-icon cve-icon
https://github.com/proftpd/proftpd cve-icon cve-icon
https://www.exploit-db.com/exploits/49697 cve-icon cve-icon
https://www.vulncheck.com/advisories/proftpd-a-remote-denial-of-service cve-icon cve-icon
History

Thu, 22 Jan 2026 23:00:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 21 Jan 2026 17:45:00 +0000

Type Values Removed Values Added
Description ProFTPD 1.3.7a contains a denial of service vulnerability that allows attackers to overwhelm the server by creating multiple simultaneous FTP connections. Attackers can repeatedly establish connections using threading to exhaust server connection limits and block legitimate user access.
Title ProFTPD 1.3.7a - Remote Denial of Service
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-01-22T21:57:57.241Z

Reserved: 2026-01-18T12:35:05.170Z

Link: CVE-2021-47865

cve-icon Vulnrichment

Updated: 2026-01-22T21:57:52.914Z

cve-icon NVD

Status : Received

Published: 2026-01-21T18:16:18.470

Modified: 2026-01-21T18:16:18.470

Link: CVE-2021-47865

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses