What is CVE-2021-20681?

CVE-2021-20681 is a medium-severity vulnerability in Basercms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-03-26.

How severe is CVE-2021-20681?

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

XSS in Basercms

CVE-2021-20681

Improper neutralization of JavaScript input in the page editing function of baserCMS versions prior to 4.4.5 allows remote authenticated attackers to inject an arbitrary script via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-03-26 · 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: 0.007 (52.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.4% 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

Basercms
Basercms Users Community — versions versions prior to 4.4.5

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

basercms.net/security/JVN64869876 (Patch, Vendor Advisory)
jvn.jp/en/jp/JVN64869876/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20681?: CVE-2021-20681 is a medium-severity vulnerability in Basercms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-03-26.
How severe is CVE-2021-20681?: Medium severity. CVSS v3 base score is 5.4 out of 10.