Mattermost ServerApplication · Mattermost

CVE-2016-11079

MEDIUM · 6.1 CVSS v3.1 Published 2020-06-19
Fix available
A fix is available. Upgrade to 3.0.0 or later.
See remediation →
68/100
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 Mattermost Server before 3.0.0. It allows XSS via a redirect URL.

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 confidence

Mattermost Server before version 3.0.0 contains a Cross-Site Scripting (XSS) vulnerability in its redirect URL handling. The application fails to properly sanitize or encode redirect URL parameters, allowing attackers to inject malicious JavaScript that executes in the context of a victim's browser when they interact with a crafted redirect link.

MitigationUpgrade Mattermost Server to version 3.0.0 or later. If immediate upgrading is not feasible, implement proper input validation and output encoding on all redirect URL parameters to neutralize script injection attempts.

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
Mattermost ServerApplication
Affected:< 3.0.0

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
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Mattermost Server version
    Access the Mattermost System Console via the web UI, navigate to About > Mattermost, or query the API endpoint /api/v1/system/status to retrieve the server version string
    Affected if The reported version is lower than 3.0.0 (for example, 2.x.x, 1.x.x)
  2. Locate Mattermost configuration file
    Identify the mattermost.cfg or config.json file in the Mattermost installation directory (commonly under /opt/mattermost or the application root)
    Affected if The configuration file exists and contains redirect-related settings (such as SiteURL, LandingPage, or custom redirect parameters)
  3. Inspect redirect URL parameters in use
    Review web server logs or proxy access logs for incoming requests to Mattermost that contain redirect= or next= query parameters
    Affected if Redirect parameters are being processed by the server without visible sanitization in the logs or application behavior
  4. Verify web application behavior with crafted redirect URL
    If permitted in a non-production environment, attempt to access a known Mattermost page with a redirect parameter set to a test value (such as redirect=javascript:alert(1)) and observe whether the value is reflected in the response
    Affected if The test redirect value is reflected in the HTML response without encoding or is used in a Location header

A user is affected if their Mattermost Server installation is version 2.x.x or lower and the server processes redirect URL parameters that are not sanitized before use.

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 3.0.0 or later
Fixed in 3.0.0
Interim mitigation

Upgrade Mattermost Server to version 3.0.0 or later. If immediate upgrading is not feasible, implement proper input validation and output encoding on all redirect URL parameters to neutralize script injection attempts.

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2016-11079 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-11079 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