CVE-2021-47865

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.

CVSS v4.0

8.7 HIGHCVSS: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

CVSS v3.1

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.56% chance of exploitation in the next 30 days, 44th percentile

Published

2026-01-21

Updated

2026-04-07

Proof-of-concept exploits (1)

• https://www.exploit-db.com/exploits/49697

References

• CVE Record
• NVD entry

Related

• CVE-2021-47864
• CVE-2021-47866
• CVE-2021-47863
• CVE-2021-47867
• CVE-2021-47862
• CVE-2021-47868