CVE-2021-35302
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 · uneditedIncorrect Access Control for linked Tickets in Zammad 1.0.x up to 4.0.0 allows remote attackers to obtain sensitive information.
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 confidenceZammad help desk software versions 1.0.x through 4.0.0 contains an incorrect access control vulnerability in its ticket linking functionality. Remote attackers can exploit improper authorization checks on linked tickets to view sensitive information from tickets they would not normally have permission to access.
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>= 1.0.0, <= 4.0.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Determine installed Zammad versionAccess the Zammad admin interface or run the command-line tool to retrieve the current software version (e.g., via the web UI version info or running 'zammad --version' if CLI access is available).Affected if The installed version falls within the range >= 1.0.0 and <= 4.0.0.
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Verify ticket linking functionality is accessibleConfirm that the ticket linking feature is enabled and accessible to users within the Zammad instance. Check admin settings under 'Ticket' or 'Link' configurations to see if linking is permitted.Affected if Ticket linking is enabled and users have the ability to create links between tickets.
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Inspect ticket access control configurationsReview the group permission settings in Zammad admin panel under 'Groups' and verify which user roles have access to which ticket groups. Pay particular attention to cross-group ticket access rules.Affected if Users have roles that permit ticket linking across groups where they lack full read access to the linked tickets.
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Audit recent ticket link activityReview ticket audit logs or activity logs for instances where users accessed tickets via link references that should fall outside their assigned group permissions.Affected if Audit logs show users accessed tickets through linking functionality that they would not normally have permission to view based on their group assignments.
A Zammad installation is affected if it runs version 1.0.0 through 4.0.0 and has ticket linking enabled with group-based access controls that permit users to link to tickets outside their permission scope.
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 dataUpgrade Zammad to version 4.0.1 or later to obtain the security patch. If immediate patching is not possible, review and restrict user group permissions for ticket access controls as a temporary mitigation.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-35302 — 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-2021-35302 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
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