PT-2026-3817 · Proftpd+1 · Proftpd+1

Xynmaps · CVE-2021-47865 · Published 2026-01-21 · Updated 2026-01-21

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

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

Name of the Vulnerable Software and Affected Versions ProFTPD version 1.3.7a

Description A denial of service issue allows attackers to overwhelm the server by creating multiple simultaneous FTP connections. By repeatedly establishing connections using threading, attackers can exhaust server connection limits and block legitimate user access.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Allocation of Resources Without Limits

Weakness Enumeration

CWE-770

Related Identifiers

CVE-2021-47865

Affected Products

Proftpd

Proftpd-Dfsg

References · 10

• 🔥 https://exploit-db.com/exploits/49697 · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2021-47865 · Security Note
• https://osv.dev/vulnerability/CVE-2021-47865 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-47865 · Security Note
• https://ubuntu.com/security/CVE-2021-47865 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47865 · Vendor Advisory
• https://github.com/proftpd/proftpd · Note
• https://github.com/proftpd/proftpd/issues/1298 · Note
• http://proftpd.org · Note
• https://vulncheck.com/advisories/proftpd-a-remote-denial-of-service · Note