CVE-2021-20627
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 · uneditedCross-site scripting vulnerability in Address Book of Cybozu Office 10.0.0 to 10.8.4 allows remote attackers 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 confidenceStored cross-site scripting (XSS) vulnerability in the Address Book component of Cybozu Office versions 10.0.0 through 10.8.4 allows remote unauthenticated attackers to inject arbitrary JavaScript or HTML payloads via unspecified input vectors. When users access the Address Book, the malicious script executes in their browser session, potentially enabling session hijacking, credential theft, or phishing attacks.
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>= 10.0.0, <= 10.8.4CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Cybozu Office versionLocate the Cybozu Office version information through the administrative console, system settings, or by accessing the login page footer which typically displays the version number. Alternatively, check the product installation directory for version manifest files.Affected if The installed version is 10.0.0, 10.8.4, or any version in between these bounds.
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Confirm Address Book component is activeLog into Cybozu Office as an administrator and navigate to the system settings or module management section to verify whether the Address Book application module is enabled and accessible to users.Affected if The Address Book module is enabled and users have permissions to access it.
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Inspect Address Book entries for injected scriptsAccess the Address Book functionality directly and review all contact entries, particularly fields that accept user-supplied input such as name, email, company, and notes fields. Look for suspicious script tags, JavaScript event handlers, or encoded payloads.Affected if Any Address Book entry contains script tags, javascript: URLs, or HTML elements with event handlers such as onload, onerror, or onmouseover.
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Review web server and application logsExamine Cybozu Office server logs and web server access logs for unusual requests targeting the Address Book API endpoint, especially those containing XSS payloads or unusual character sequences in parameters related to address book operations.Affected if Logs show requests to Address Book functions containing XSS probe patterns or successful injection attempts.
The environment is affected if Cybozu Office version 10.0.0 through 10.8.4 is installed AND the Address Book component is enabled, regardless of whether exploitation is confirmed.
Generated from the published advisory. Verify against your own configuration.
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 dataApply Cybozu Office version 10.8.5 or later which contains the vendor patch. As a compensating control, implement output encoding and Content Security Policy headers to mitigate XSS execution until patching is complete.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20627 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-20627 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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