What is CVE-2020-21494?

CVE-2020-21494 is a medium-severity vulnerability in Xiuno Xiunobbs, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-04.

How severe is CVE-2020-21494?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Xiuno Xiunobbs

CVE-2020-21494

A cross-site scripting (XSS) vulnerability in the component install\install.sql of Xiuno BBS 4.0.4 allows attackers to execute arbitrary web scripts or HTML via changing the doctype value to 0.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-10-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.2th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Xiuno Xiunobbs — versions 4.0.4

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

gitee.com/xiuno/xiunobbs/issues/I16BHH (Third Party Advisory, Issue Tracking)
github.com/wanghaiwei/xiuno-docker/issues/4 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-21494?: CVE-2020-21494 is a medium-severity vulnerability in Xiuno Xiunobbs, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-04.
How severe is CVE-2020-21494?: Medium severity. CVSS v3 base score is 6.1 out of 10.