CVE-2021-47865

Published Jan 21, 2026

Last updated 2 months ago

CVSS high 8.7
Port (21)

Overview

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.
Source
disclosure@vulncheck.com
NVD status
Awaiting Analysis

Risk scores

CVSS 4.0

Type
Secondary
Base score
8.7
Impact score
-
Exploitability score
-
Vector string
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity
HIGH

CVSS 3.1

Type
Secondary
Base score
7.5
Impact score
3.6
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity
HIGH

Weaknesses

disclosure@vulncheck.com
CWE-770

Social media

Hype score
Not currently trending

Related CVEs

  1. A flaw was found in the FTP GVfs backend. A remote attacker could exploit this input validation vulnerability by supplying specially crafted file paths containing carriage return and line feed (CRLF) sequences. These unsanitized sequences allow the attacker to terminate intended FTP commands and inject arbitrary FTP commands, potentially leading to arbitrary code execution or other severe impacts.•CVE-2026-28296
  2. The `basic-ftp` FTP client library for Node.js contains a path traversal vulnerability (CWE-22) in versions prior to 5.2.0 in the `downloadToDir()` method. A malicious FTP server can send directory listings with filenames containing path traversal sequences (`../`) that cause files to be written outside the intended download directory. Version 5.2.0 patches the issue.•CVE-2026-27699
  3. The FTP Backup on the ADM does not properly sanitize filenames received from the FTP server when parsing directory listings. A malicious server or MITM attacker can craft filenames containing path traversal sequences, causing the client to write files outside the intended backup directory. A path traversal vulnerability may allow an attacker to overwrite arbitrary files on the system and potentially achieve privilege escalation or remote code execution. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.ROF1 as well as from ADM 5.0.0 through ADM 5.1.2.RE51.•CVE-2026-3179
  4. Core FTP LE 2.2 contains a denial of service vulnerability that allows attackers to crash the application by overwriting the account field with a large buffer. Attackers can create a text file with 20,000 repeated characters and paste it into the account field to cause the application to become unresponsive and require reinstallation.•CVE-2020-37107
  5. Monsta FTP versions 2.11 and earlier contain a vulnerability that allows unauthenticated arbitrary file uploads. This flaw enables attackers to execute arbitrary code by uploading a specially crafted file from a malicious (S)FTP server.•CVE-2025-34299

References

Sources include official advisories and independent security research.