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Remote Service ManagerApplication · Cybozu

CVE-2021-20798

MEDIUM · 5.4 CVSS v3.1 Published 2021-10-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
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 scripting vulnerability in the management screen of Cybozu Remote Service 3.1.8 to 3.1.9 allows a remote authenticated 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 Cybozu Remote Service management screen versions 3.1.8 through 3.1.9 allows authenticated remote attackers to inject arbitrary JavaScript code via unspecified input vectors. The vulnerability exists in the web interface where user-supplied data is not properly sanitized before being rendered.

MitigationImplement proper input validation and output encoding on all management screen fields; consider upgrading to a patched version if available; if immediate patching is not possible, deploy WAF rules to mitigate XSS exploitation.

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
Remote Service ManagerApplication
Affected:= 3.1.8= 3.1.9

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
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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. Identify Cybozu Remote Service Manager installation
    Check for Cybozu Remote Service Manager in your installed applications or services list. Look for the service process or web application running on your server.
    Affected if Cybozu Remote Service Manager is not installed on the system.
  2. Determine installed version
    Access the management console or check the application version information. Typically found in About or Version sections of the admin interface, or check the installed software package details.
    Affected if The installed version is exactly 3.1.8 or 3.1.9.
  3. Verify management screen accessibility
    Confirm the web-based management interface is accessible. This is typically accessed via browser to the service URL on the configured port.
    Affected if The management screen is exposed and accessible over the network.
  4. Confirm authentication method
    Check whether user authentication is configured for the management interface and whether regular users have access to input fields in the management screen.
    Affected if Authenticated users can access input fields in the management screen.

The environment is affected if Cybozu Remote Service Manager versions 3.1.8 or 3.1.9 are installed and the management screen is accessible to authenticated users.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper input validation and output encoding on all management screen fields; consider upgrading to a patched version if available; if immediate patching is not possible, deploy WAF rules to mitigate XSS exploitation.

Recommended fix Moderate confidence

Cybozu Remote Service 3.1.10 or later (verify exact fixed version in vendor release notes)

  1. 1. Identify the currently installed version of Cybozu Remote Service in your environment.
  2. 2. Download the latest version of Cybozu Remote Service from the official vendor website or support portal (kb.cybozu.support).
  3. 3. Review the release notes or security advisories for the new version to confirm it includes a fix for CVE-2021-20798.
  4. 4. Before applying the upgrade, perform a full backup of the current installation and database.
  5. 5. Test the upgrade in a staging or test environment to verify compatibility with your existing systems.
  6. 6. Apply the upgrade to the production environment following standard change management procedures.
  7. 7. After upgrading, verify that the management screen is functioning correctly and the XSS vulnerability is resolved.
Caveat Review upgrade documentation for any configuration or compatibility changes between 3.1.8/3.1.9 and the fixed version

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

Fix this in Remote Service Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2021-20798 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