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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.006 (46.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000
Affected products
- Proftpd — versions 1.3.7a
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/49697 (exploit)
- www.proftpd.org/ (product)
- github.com/proftpd/proftpd/issues/1298 (issue-tracking)
- www.vulncheck.com/advisories/proftpd-a-remote-denial-of-service (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.