CVE-2020-5566Network attack vector

Authenticated data alteration via unenforced operation restrictions

Published Apr 28, 2020 · Updated Aug 4, 2024

Improper authorization in Cybozu Garoon 4.0.0 through 4.10.3 allows remote authenticated users to alter E-mail and Messages data. The E-mail and Messages applications fail to enforce operation restrictions when processing data-changing requests; Cybozu has not published the affected endpoint or authorization check. A valid Garoon account and network access are required; E-mail is affected only through 4.0.2, while Messages remains affected through 4.10.3.

CVSS severity4.3
Medium
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper authorization in Cybozu Garoon 4.0.0 through 4.10.3 allows remote authenticated users to alter E-mail and Messages data. The E-mail and Messages applications fail to enforce operation restrictions when processing data-changing requests; Cybozu has not published the affected endpoint or authorization check. A valid Garoon account and network access are required; E-mail is affected only through 4.0.2, while Messages remains affected through 4.10.3.

The record

CVE
CVE-2020-5566
Published
Apr 28, 2020
Updated
Aug 4, 2024
Vendor
Cybozu
Product
Garoon
Classifications
CWE-285
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 28, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 to 4.10.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cybozu · Garoonversion=4.0.0 to 4.10.3

Published CVSS scores

4.3JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
4.0JPCERT/CCAV:N/AC:L/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo