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Vulnerabilities

Vulnerability · 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.

Published Jan 21, 2026 · catalog updated Apr 7, 2026 · ProFTPD ProFTPD

Last checked Nov 4, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-47865. EPSS is 0.60%. Act only if a listed version of ProFTPD ProFTPD is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.60%
Remediation
Vendor / distro source
Affected products
vendor ProFTPD ProFTPD 1.3.7a

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor ProFTPD ProFTPD 1.3.7a1.3.7a

How to fix CVE-2021-47865

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-47865. EPSS is 0.60%. Act only if a listed version of ProFTPD ProFTPD is installed.

Which versions are affected?

Compare what you have installed with ProFTPD ProFTPD 1.3.7a 1.3.7a. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.60%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 21, 2026 · EUVD

    Detected

    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.

  2. Apr 7, 2026 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2021-47865

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-47865

    30-day exploitation probability 0.60%

    first.org
  • EUVDVulnerability recordEUVD-2026-3621

    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

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • FIRST EPSSNov 3, 2026
  • EUVDNov 2, 2026