What is CVE-2020-21656?

CVE-2020-21656 is a medium-severity vulnerability in Xyhcms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-10-06.

How severe is CVE-2020-21656?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Xyhcms

CVE-2020-21656

XYHCMS v3.6 contains a stored cross-site scripting (XSS) vulnerability in the component xyhai.php?s=/Link/index.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-10-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (36.8th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Xyhcms — versions 3.6

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/gosea/xyhcms3/issues/2 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-21656?: CVE-2020-21656 is a medium-severity vulnerability in Xyhcms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-10-06.
How severe is CVE-2020-21656?: Medium severity. CVSS v3 base score is 5.4 out of 10.