What is CVE-2021-20667?

CVE-2021-20667 is a medium-severity vulnerability in Weseek Growi, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-03-10.

How severe is CVE-2021-20667?

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

XSS in Weseek Growi

CVE-2021-20667

Stored cross-site scripting vulnerability due to inadequate CSP (Content Security Policy) configuration in GROWI versions v4.2.2 and earlier allows remote authenticated attackers to inject an arbitrary script via a specially crafted content.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-03-10 · 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 (50.4th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.007 · change: +0.000

Affected products

Weseek Growi
Weseek, Inc. Growi — versions versions v4.2.2 and earlier

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

weseek.co.jp/security/2021/03/08/vulnerability/growi-prevent-multiple-xss/ (Vendor Advisory)
jvn.jp/en/vu/JVNVU94889258/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20667?: CVE-2021-20667 is a medium-severity vulnerability in Weseek Growi, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-03-10.
How severe is CVE-2021-20667?: Medium severity. CVSS v3 base score is 5.4 out of 10.