OfficeApplication · Cybozu

CVE-2021-20631

MEDIUM · 6.5 CVSS v3.1 Published 2021-03-18
Fix available
A fix is available. Upgrade to after 10.8.4 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

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
Improper input validation vulnerability in Custom App of Cybozu Office 10.0.0 to 10.8.4 allows authenticated attacker to alter the data of Custom App 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

Improper input validation vulnerability in the Custom App feature of Cybozu Office versions 10.0.0 through 10.8.4 allows authenticated attackers to alter Custom App data through unspecified vectors. The vulnerability stems from inadequate validation of user-supplied input before it is processed, potentially enabling data manipulation.

MitigationUpdate Cybozu Office to version 10.8.5 or later, which contains the patch for this vulnerability. Until patching is possible, limit access to the Custom App functionality to trusted users only.

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
OfficeApplication
Affected:>= 10.0.0, <= 10.8.4

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
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 Office version
    Access the system administration panel or check the product version through the help/about section in Cybozu Office. The version is typically displayed in the system settings or footer of the administrative interface.
    Affected if The installed version falls within the range 10.0.0 through 10.8.4 (versions below 10.8.5).
  2. Confirm Custom App feature is active
    Navigate to the Custom App management section within the Cybozu Office administration interface. Check if any custom applications have been created or if the Custom App module is enabled in the system.
    Affected if The Custom App feature is enabled or has custom applications configured in the system.
  3. Review user access to Custom App
    Examine the user permissions and access controls for the Custom App functionality through the administration panel. Check which users or groups have permission to create or modify custom applications.
    Affected if There are users with access to the Custom App feature, particularly those with create or edit permissions.

If Cybozu Office version is 10.0.0 through 10.8.4 AND the Custom App feature is enabled with active users, the environment is potentially affected by this vulnerability.

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.

From vendor data
Upgrade available Upgrade to a release after 10.8.4
Interim mitigation

Update Cybozu Office to version 10.8.5 or later, which contains the patch for this vulnerability. Until patching is possible, limit access to the Custom App functionality to trusted users only.

Fix this in Office 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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-20631 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2021-20631 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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