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GaroonApplication · Cybozu

CVE-2021-20758

HIGH · 8.0 CVSS v3.1 Published 2021-08-18
Fix available
A fix is available. Upgrade to after 5.0.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Cross-site request forgery (CSRF) vulnerability in Message of Cybozu Garoon 4.0.0 to 5.0.2 allows a remote authenticated attacker to hijack the authentication of administrators and perform an arbitrary operation via unspecified vectors.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a Cross-Site Request Forgery (CSRF) vulnerability in the Message component of Cybozu Garoon versions 4.0.0 through 5.0.2. An authenticated attacker can craft malicious requests that trick administrator users into unknowingly executing arbitrary operations in the application, leveraging the trusted authentication state of the victim.

MitigationApply the vendor patch/upgrade to a version beyond 5.0.2 as specified in Cybozu's security advisory. If immediate patching is not possible, implement CSRF tokens and validate Referer/Origin headers for all administrative actions in the Message module.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
GaroonApplication
Affected:>= 4.0.0, <= 5.0.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Cybozu Garoon installation and version
    Access the Cybozu Garoon administrator control panel (typically at /g/ or /garoon/) and navigate to System Settings > System Information to view the installed version number. Alternatively, check the installation manifest or version file in the Garoon installation directory.
    Affected if The installed version is 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.5.0, 4.5.1, 4.5.2, 4.5.3, 4.6.0, 4.6.1, 4.6.2, 4.6.3, 4.7.0, 4.7.1, 4.7.2, 4.7.3, 4.8.0, 4.8.1, 4.8.2, 4.9.0, 4.9.1, 4.9.2, 4.9.3, 5.0.0, 5.0.1, or 5.0.2.
  2. Confirm Message module is enabled
    In the Garoon admin panel, navigate to Application Settings > Message (or Mail) settings to verify the Message component is active and accessible to users. CSRF exploitation requires the vulnerable component to be enabled.
    Affected if The Message module is enabled and accessible to authenticated users.
  3. Check for CSRF token validation in Message module
    Inspect HTTP requests when using the Message component (e.g., sending a message, managing folders). Verify that each POST request to Message-related endpoints includes a CSRF token parameter (commonly named token, csrf_token, or similar) and that the server validates it. If requests succeed without a token, the protection is missing.
    Affected if Message module requests do not require and validate a CSRF token parameter.
  4. Verify Referer/Origin header validation
    Submit a POST request to a Message endpoint with a mismatched or missing Referer/Origin header (e.g., from an external site). Observe whether the server accepts or rejects the request. Proper protection rejects requests with invalid headers.
    Affected if The server accepts Message module requests with mismatched or missing Referer/Origin headers.

You are affected if Cybozu Garoon version 4.0.0 through 5.0.2 is installed, the Message module is enabled, and CSRF token validation or Referer/Origin header checks are missing from the Message component.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 5.0.2
Interim mitigation

Apply the vendor patch/upgrade to a version beyond 5.0.2 as specified in Cybozu's security advisory. If immediate patching is not possible, implement CSRF tokens and validate Referer/Origin headers for all administrative actions in the Message module.

Recommended fix Moderate confidence

Garoon 5.0.3 or later

  1. 1. Back up your current Garoon installation and database.
  2. 2. Obtain the latest version of Garoon from the official Cybozu download page or your licensed distribution channel.
  3. 3. Review the Garoon upgrade guide for your current version.
  4. 4. Execute the upgrade following Cybozu's standard upgrade procedure.
  5. 5. Verify that the Message module functions correctly after upgrade.
  6. 6. Confirm the Garoon version is 5.0.3 or later.
Caveat Review Cybozu release notes for any functional changes between your current version and 5.0.x

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Garoon Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-20758 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data