What is CVE-2020-28864?

CVE-2020-28864 is a critical-severity vulnerability in Winscp, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-11-23.

How severe is CVE-2020-28864?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Winscp

CVE-2020-28864

Buffer overflow in WinSCP 5.17.8 allows a malicious FTP server to cause a denial of service or possibly have other unspecified impact via a long file name.

Vulnerability class: Buffer Overflow

Published 2020-11-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.028 (86.2th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 86.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.028 · newest: 0.028 · change: 0.000

Affected products

Winscp — versions 5.17.8

Weakness classification (CWE)

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

References

winscp.net/forum/viewtopic.php (Vendor Advisory)
winscp.net/tracker/1924 (Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2020-28864?: CVE-2020-28864 is a critical-severity vulnerability in Winscp, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-11-23.
How severe is CVE-2020-28864?: Critical severity. CVSS v3 base score is 9.8 out of 10.