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ZammadApplication

CVE-2020-26033

MEDIUM · 5.4 CVSS v3.1 Published 2020-12-28
Fix available
A fix is available. Upgrade to 3.4.1 or later.
See remediation →
61/100
Remediation priority · Elevated
Remotely reachable No privileges

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
An issue was discovered in Zammad before 3.4.1. The Tag and Link REST API endpoints (for add and delete) lack a CSRF token check.

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 confidence

The Tag and Link REST API endpoints in Zammad before version 3.4.1 do not validate CSRF tokens on add and delete operations, allowing attackers to craft malicious requests that execute actions on behalf of authenticated users.

MitigationUpgrade Zammad to version 3.4.1 or later which includes CSRF token validation for the affected API endpoints.

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
ZammadApplication
Affected:>= 1.0.0, < 3.4.1

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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 installed Zammad version
    Run `zammad --version` or check the package manager (e.g., `dpkg -l | grep zammad`, `rpm -qa | grep zammad`) or access the admin panel under System > Information to view the version number
    Affected if version is lower than 3.4.1 (e.g., 3.4.0, 3.3.x, 3.2.x, etc.)
  2. Confirm REST API is enabled
    Check if the API is accessible by querying the API documentation endpoint (typically /api/v1/) or verify in the admin panel under Settings > System > API that the REST API is turned on
    Affected if REST API is enabled and version is below 3.4.1
  3. Verify Tag API endpoint exposure
    Attempt a GET request to the Tag API endpoint (e.g., `curl -k https://your-zammad-host/api/v1/tags`) with valid authentication credentials to confirm the endpoint responds
    Affected if Tag API endpoint returns data and version is below 3.4.1
  4. Verify Link API endpoint exposure
    Attempt a GET request to the Link API endpoint (e.g., `curl -k https://your-zammad-host/api/v1/links`) with valid authentication credentials to confirm the endpoint responds
    Affected if Link API endpoint returns data and version is below 3.4.1

If Zammad version is 1.0.0 or higher but lower than 3.4.1 AND the REST API with Tag/Link endpoints is enabled, the environment is vulnerable to CSRF attacks on these endpoints.

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 3.4.1 or later
Fixed in 3.4.1
Interim mitigation

Upgrade Zammad to version 3.4.1 or later which includes CSRF token validation for the affected API endpoints.

Fix this in Zammad Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,440
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,904.

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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-2020-26033 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