CVE-2016-3406
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 · uneditedMultiple cross-site request forgery (CSRF) vulnerabilities in Zimbra Collaboration before 8.7.0 allow remote attackers to hijack the authentication of unspecified victims via vectors involving (1) the Client uploader extension or (2) extension REST handlers, aka bugs 104294 and 104456.
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 confidenceMultiple Cross-Site Request Forgery (CSRF) vulnerabilities in Zimbra Collaboration before version 8.7.0 allow remote attackers to hijack the authentication of unspecified victims. The vulnerabilities exist in the Client uploader extension and extension REST handlers (bugs 104294 and 104456). Successful exploitation enables attackers to perform unintended actions on behalf of authenticated users.
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<= 8.6.0CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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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Check installed Zimbra Collaboration versionRun 'zmcontrol -v' as the zimbra user, or check the installed package version using the system package manager (rpm, dpkg) for zimbra-core or similar packagesAffected if The reported version is 8.6.0 or earlier (any version below 8.7.0)
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Verify Zimbra web client is accessibleConfirm the Zimbra web interface (typically ports 80, 443, 8080, or 8443) is reachable and respondingAffected if The Zimbra web service is exposed and the version is vulnerable (8.6.0 or below)
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Identify if Client uploader extension is enabledReview Zimbra configuration files in /opt/zimbra/ for settings related to the upload endpoint or the uploader extension; check /opt/zimbra/jetty/webapps/zimbra/public/upload/ or similar paths if they existAffected if The uploader extension is accessible and the Zimbra version is in the affected range (8.6.0 or below)
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Identify if REST handlers are accessibleTest common REST endpoints such as /service/extension/ or /service/rest/ paths; review Zimbra's proxy and servlet configurations in /opt/zimbra/jetty/etc/Affected if REST handlers are exposed without anti-CSRF protection and the Zimbra version is in the affected range (8.6.0 or below)
You are affected if your installed Zimbra Collaboration Suite version is 8.6.0 or earlier and the web interface with its client uploader extension or REST handlers is accessible to potential attackers.
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 Zimbra Collaboration to version 8.7.0 or later to patch the CSRF vulnerabilities. Additionally, implement anti-CSRF tokens for state-changing operations and validate the Origin/Referer headers on sensitive requests.
- 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-2016-3406 — 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-2016-3406 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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