What is CVE-2021-20807?

CVE-2021-20807 is a medium-severity vulnerability in Cybozu Remote Service Manager, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-13.

How severe is CVE-2021-20807?

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

XSS in Cybozu Remote Service Manager

CVE-2021-20807

Cross-site scripting vulnerability in the management screen of Cybozu Remote Service 3.0.0 to 3.1.9 allows a remote attacker to inject an arbitrary script via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-10-13 · 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: 0.008 (53.3th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Cybozu Remote Service Manager
Cybozu, Inc. Cybozu Remote Service — versions 3.0.0 to 3.1.9

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

jvn.jp/en/jp/JVN52694228/index.html (Third Party Advisory)
kb.cybozu.support/article/37430 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-20807?: CVE-2021-20807 is a medium-severity vulnerability in Cybozu Remote Service Manager, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-13.
How severe is CVE-2021-20807?: Medium severity. CVSS v3 base score is 6.1 out of 10.