CVE-2021-42088
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 · uneditedAn issue was discovered in Zammad before 4.1.1. The Chat functionality allows XSS because clipboard data is mishandled.
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 confidenceZammad help desk software before version 4.1.1 contains a cross-site scripting (XSS) vulnerability in its Chat feature. The vulnerability stems from improper handling of clipboard data, allowing attackers to inject malicious scripts that execute in the context of other users' browsers when they view or interact with chat messages.
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< 4.1.1CVSS 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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Verify Zammad installationIdentify if Zammad help desk software is installed in your environment. Check for Zammad directories, services, or the web application accessible on expected hostnames/ports.Affected if Zammad is not present in the environment
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Determine installed Zammad versionLocate the installed Zammad version number. This is typically accessible via the web interface admin panel, command-line tools, or version files in the installation directory.Affected if Unable to determine the version from the system
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Compare version to affected rangeCompare your installed version against the affected range: versions prior to 4.1.1 are vulnerable. Check if your version number is less than 4.1.1.Affected if Installed version is 4.1.0 or earlier (any version below 4.1.1)
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Confirm Chat feature is activeVerify whether the Chat module is enabled and accessible in your Zammad instance. Check the admin settings or configuration to determine if any users have access to chat functionality.Affected if Chat feature is enabled and users can send or receive chat messages
You are affected if Zammad version is below 4.1.1 and the Chat feature is enabled in your environment.
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.
dbcve · scoped4.1.1
Upgrade Zammad to version 4.1.1 or later to receive the patch for this XSS vulnerability. If immediate upgrade is not possible, implement input sanitization on clipboard data within the chat module and restrict chat features until the upgrade can be completed.
4.1.1
- Backup your Zammad database and application data before proceeding with the upgrade
- Stop the Zammad application services
- Upgrade Zammad to version 4.1.1 or later using your package manager or upgrade method (e.g., apt-get update && apt-get install zammad for Debian/Ubuntu, or yum update zammad for RHEL/CentOS)
- Start the Zammad application services
- Verify the upgrade was successful by checking the Zammad version in the web interface or via command line
- Clear any cached data to ensure the new version is fully loaded
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42088 — 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-2021-42088 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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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.
- 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