What is CVE-2020-5566?

CVE-2020-5566 is a medium-severity vulnerability in Cybozu Garoon. CVSS score: 4.3/10. Published 2020-04-28.

How severe is CVE-2020-5566?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Cybozu Garoon

CVE-2020-5566

Improper authorization vulnerability in Cybozu Garoon 4.0.0 to 4.10.3 allows remote authenticated attackers to alter the application's data via the applications 'E-mail' and 'Messages'.

Published 2020-04-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.1th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Cybozu Garoon
Cybozu, Inc. Cybozu Garoon — versions 4.0.0 to 4.10.3

References

jvn.jp/en/jp/JVN35649781/index.html (Third Party Advisory)
kb.cybozu.support/article/36113/ (Vendor Advisory)

Frequently asked questions

What is CVE-2020-5566?: CVE-2020-5566 is a medium-severity vulnerability in Cybozu Garoon. CVSS score: 4.3/10. Published 2020-04-28.
How severe is CVE-2020-5566?: Medium severity. CVSS v3 base score is 4.3 out of 10.