CVE-2021-35299
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 in Zammad 1.0.x up to 4.0.0 allows attackers to obtain sensitive information via email connection configuration probing.
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 confidenceThis is an Incorrect Access Control vulnerability in Zammad versions 1.0.x through 4.0.0 that allows attackers to probe the email connection configuration and obtain sensitive information. The vulnerability stems from insufficient authorization checks on endpoints or functions related to email settings, enabling unauthorized disclosure of configuration details.
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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.
-
Identify Zammad installation and versionLocate the Zammad installation directory and check the version file or use the Zammad command-line tool to retrieve the installed version number. Common locations include /opt/zammad or the application's about page in the web interface.Affected if The installed version is 1.0.x, 2.x, 3.x, or 4.0.0 exactly.
-
Confirm email settings module is in useAccess the Zammad administrative interface and navigate to the Email settings or Channels configuration section. Verify whether email integration (SMTP/IMAP/POP3) has been configured or is accessible.Affected if Email settings or channels are configured or accessible within the application.
-
Test authorization on email configuration endpointsUsing a web proxy or curl, attempt to access email-related API endpoints (such as /api/v1/channels/email or similar paths) while authenticated as a non-administrator user or without authentication. Observe whether configuration details are returned.Affected if The endpoint returns email configuration details, credentials, or sensitive connection parameters without requiring admin-level authorization.
-
Review user role permissionsExamine the role and permission settings for non-admin user accounts in Zammad. Check if standard users or agents have access to system configuration or email settings areas.Affected if Non-administrator accounts have elevated permissions allowing access to email configuration areas.
You are affected if Zammad version is 4.0.0 or earlier and email configuration endpoints are accessible to unauthorized or low-privilege users.
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 which contains the security patch. Additionally, review and restrict access to administrative configuration interfaces and monitor for unauthorized probing attempts.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-35299 — 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-2021-35299 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
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.
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