CVE-2021-20758Network attack vector

Unintended Message operations via cross-site request forgery

Published Aug 18, 2021 · Updated Aug 3, 2024

Cross-site request forgery in Cybozu Garoon Message 4.0.0 through 5.0.2 allows remote attackers to trigger unintended operations. Cybozu has not published the affected endpoint or request-validation error, and it withholds reproduction steps because disclosure could enable attacks. Exploitation requires user interaction during an authenticated Garoon session; the vendor reports limited integrity impact only.

CVSS severity4.3
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Cybozu Garoon Message 4.0.0 through 5.0.2 allows remote attackers to trigger unintended operations. Cybozu has not published the affected endpoint or request-validation error, and it withholds reproduction steps because disclosure could enable attacks. Exploitation requires user interaction during an authenticated Garoon session; the vendor reports limited integrity impact only.

The record

CVE
CVE-2021-20758
Published
Aug 18, 2021
Updated
Aug 3, 2024
Vendor
Cybozu
Product
Garoon
Classifications
CWE-352
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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 5.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cybozu · Garoonversion=4.0.0 to 5.0.2

Published CVSS scores

2.6JPCERT/CCAV:N/AC:H/Au:N/C:N/I:P/A:N
8.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
4.3JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
6.0NIST NVDAV:N/AC:M/Au:S/C:P/I:P/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)

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

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Your stack

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