CVE-2016-3999
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 scripting (XSS) vulnerabilities in Zimbra Collaboration before 8.7.0 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka bugs 104552 and 104703.
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 confidenceCross-site scripting (XSS) vulnerabilities in Zimbra Collaboration prior to version 8.7.0 allow remote attackers to inject arbitrary web script or HTML through unspecified vectors (bugs 104552 and 104703). This is a medium-severity issue indicating the attack vector is likely network-exploitable without authentication but requires user interaction or specific conditions.
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
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/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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Identify if Zimbra Collaboration Suite is installedLook for Zimbra-related processes running on the system, or check for Zimbra installation directories and services. Common locations include /opt/zimbra or standard application installation paths.Affected if Zimbra Collaboration Suite is present on the system
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Determine the installed Zimbra versionUse the Zimbra command line utility (zmcontrol -v) or check the version file in the Zimbra installation directory. Alternatively, access the Zimbra admin web interface and look at the server status or about section.Affected if The version returned is 8.6.0 or earlier (8.6.0, 8.5.x, 8.0.x, or older)
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Confirm the Zimbra web interface is accessibleVerify that the Zimbra web mail or admin interface is reachable via HTTP/HTTPS. This is required because XSS vulnerabilities in Zimbra target the web interface components.Affected if The web interface is exposed and operational
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Check for evidence of XSS exploitationReview web server access logs and application logs for suspicious patterns in HTTP requests that may indicate XSS attempts, such as <script> tags, JavaScript event handlers, or other HTML injection attempts in parameters that could be reflected.Affected if Unusual XSS patterns are found in logs targeting the Zimbra web application
The environment is affected if Zimbra Collaboration Suite version 8.6.0 or earlier is installed and the web interface is accessible.
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 obtain the patched versions of the software. If immediate upgrade is not feasible, consider deploying a WAF with XSS filtering rules as an interim control.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-3999 — 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-2016-3999 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
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