What is CVE-2021-47865?

CVE-2021-47865 is a high-severity vulnerability in Proftpd, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-01-21.

How severe is CVE-2021-47865?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Proftpd

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.

EPSS: 0.005 (42.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Proftpd — versions 1.3.7a

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

disclosure@vulncheck.com (exploit)
disclosure@vulncheck.com (product)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2021-47865?: CVE-2021-47865 is a high-severity vulnerability in Proftpd, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-01-21.
How severe is CVE-2021-47865?: High severity. CVSS v3 base score is 7.5 out of 10.