What is CVE-2020-21588?

CVE-2020-21588 is a medium-severity vulnerability in Coreftp Core FTP, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2021-04-02.

How severe is CVE-2020-21588?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Buffer overflow in Coreftp Core FTP

CVE-2020-21588

Buffer overflow in Core FTP LE v2.2 allows local attackers to cause a denial or service (crash) via a long string in the Setup->Users->Username editbox.

Vulnerability class: Buffer Overflow

Published 2021-04-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (14.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Coreftp Core FTP — versions 2.2

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

github.com/lonely-explorer/CoreFTP/issues/1 (Third Party Advisory)
github.com/pwnninja/CoreFTP/issues/1 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-21588?: CVE-2020-21588 is a medium-severity vulnerability in Coreftp Core FTP, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2021-04-02.
How severe is CVE-2020-21588?: Medium severity. CVSS v3 base score is 5.5 out of 10.