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GaroonApplication · Cybozu

CVE-2021-20765

MEDIUM · 6.1 CVSS v3.1 Published 2021-08-18
Fix available
A fix is available. Upgrade to after 5.0.2 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 scripting vulnerability in Bulletin of Cybozu Garoon 4.0.0 to 5.0.2 allows a remote attacker to inject an arbitrary script 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 · moderate confidence

Cross-site scripting (XSS) vulnerability in the Bulletin module of Cybozu Garoon versions 4.0.0 through 5.0.2 allows remote attackers to inject arbitrary JavaScript or HTML via unspecified vectors in Bulletin content, potentially executing in the context of other users' sessions.

MitigationApply vendor patch for CVE-2021-20765; implement input validation and output encoding for Bulletin content fields to neutralize script injection vectors.

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
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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. Confirm Cybozu Garoon installation
    Check your system for Cybozu Garoon by reviewing installed software, checking the web application banner, or accessing the login page and examining the server response headers or footer for version information.
    Affected if Cybozu Garoon is not installed on the system.
  2. Identify Garoon version number
    Access the Garoon administration panel or login page, and locate the version number typically displayed in the footer, about page, or system information section. Compare this against the affected range 4.0.0 to 5.0.2.
    Affected if The installed version falls within 4.0.0 through 5.0.2 inclusive.
  3. Verify Bulletin module is accessible
    Log into Garoon as a standard user or administrator and navigate to the Bulletin (BBS) module from the main menu to confirm it is active and usable.
    Affected if The Bulletin module is enabled and users can create or view bulletin content.
  4. Review Bulletin content creation permissions
    Check the Garoon administration settings under the Bulletin module to see which users or groups have permission to create or edit bulletin posts.
    Affected if Users other than administrators have the ability to post content in the Bulletin module.

A user is affected if Cybozu Garoon version 4.0.0 through 5.0.2 is installed with the Bulletin module enabled and accessible to users who can create content.

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 vendor patch for CVE-2021-20765; implement input validation and output encoding for Bulletin content fields to neutralize script injection vectors.

Recommended fix Moderate confidence

Garoon 5.0.3 or later

  1. 1. Back up your current Garoon database and configuration files.
  2. 2. Download Garoon version 5.0.3 or later from the official Cybozu download page.
  3. 3. Stop the Garoon service before applying the upgrade.
  4. 4. Run the installer/upgrade process following Cybozu's standard upgrade documentation.
  5. 5. Verify the upgrade was successful by logging into Garoon.
  6. 6. Test the Bulletin board functionality to confirm the XSS fix is applied.
  7. 7. Restart the Garoon service and monitor for any issues.
Caveat Standard minor version upgrade with no expected breaking changes; review release notes for any minor compatibility notes

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
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

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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-2021-20765 in production — separate from our analysis above.

No notes yet

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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