License ServerApplication · Citrix
CVE-2016-6273
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 · uneditedThe lmadmin component in Flexera FlexNet Publisher (aka Flex License Manager) before 2015 SP5 and 2016 before R1 SP1, as used by Citrix License Server for Windows before 11.14.0.1 and Citrix License Server VPX before 11.14.0.1, allows remote attackers to cause a denial of service (crash) via a type 2F packet with a '01 19' opcode.
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 confidenceA denial of service vulnerability exists in the lmadmin component of Flexera FlexNet Publisher (Flex License Manager) and Citrix License Server. Remote attackers can cause the license server to crash by sending a specially crafted type 2F packet with a '01 19' opcode.
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
License ServerApplication
<= 11.14.0.0
License Server VpxApplication
<= 11.14.0.0CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify if Citrix License Server is installedCheck for the presence of the Citrix License Server installation. On Windows, look for the service named 'Citrix License Server' or check Program Files for Citrix License Server directory. On Linux, check /opt/citrix/licensing/ or similar paths.Affected if Citrix License Server or Citrix License Server Vpx is installed and the version is 11.14.0.0 or lower
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Determine the installed version of Citrix License ServerRun the vendor-provided version check command or inspect the license server's about/version information. On Windows, this may be available through the license server management interface or Windows Programs and Features. On Linux, check the version using the licensing utility or rpm/dpkg query.Affected if The installed version is 11.14.0.0 or any version lower than 11.14.0.1
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Verify if the lmadmin component is runningCheck if the lmadmin license manager daemon is active. On Windows, verify the 'FlexNet Licensing Service' or 'Citrix License Server' service is running. On Linux, check for running lmadmin or vendorad processes using 'ps aux | grep lmadmin' or similar.Affected if The lmadmin component is running and exposed to network traffic, allowing specially crafted type 2F packets with '01 19' opcode to reach the service
You are affected if Citrix License Server or Citrix License Server Vpx is installed with version 11.14.0.0 or lower and the lmadmin service is running and network-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 FlexNet Publisher to 2015 SP5 or 2016 R1 SP1 or later, and Citrix License Server to version 11.14.0.1 or later.
Fix this in License Server
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-6273 — 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-2016-6273 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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