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Fencer Vulns
high 7.5

CVE-2021-30047 json

VSFTPD 3.0.3 allows attackers to cause a denial of service due to limited number of connections allowed.

published 2023-08-22 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-16991

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known, plus a Nuclei check

Summary

VSFTPD 3.0.3 allows attackers to cause a denial of service due to limited number of connections allowed.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-30047 updated cvss 7.5

vsftpd: denial of service due to limited number of connections allowed

  • Red Hat Enterprise Linux 6 vsftpd Red Hat Enterprise Linux 7 vsftpd, vsftpd-sysvinit
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 vsftpd Red Hat Enterprise Linux 9 vsftpd
    not affected: inline mitigations already exist
  • Red Hat Enterprise Linux 10 vsftpd
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

3.21% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template vsftpd < 3.0.3 - DoS nuclei detection template
  • exploit-db.com https://www.exploit-db.com/exploits/49719 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.