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XenappApplication · Citrix

CVE-2016-6493

CRITICAL · 9.8 CVSS v3.0 Published 2016-08-19
Fix available
A fix is available. Upgrade to after 7.8 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Citrix XenApp 6.x before 6.5 HRP07 and 7.x before 7.9 and Citrix XenDesktop before 7.9 might allow attackers to weaken an unspecified security mitigation via vectors related to memory permission.

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

This is a memory permission vulnerability in Citrix XenApp 6.x before 6.5 HRP07, XenApp 7.x before 7.9, and XenDesktop before 7.9 that allows attackers to weaken an unspecified security mitigation mechanism. The vulnerability involves vectors related to memory permission settings, potentially undermining memory protection features.

MitigationUpgrade Citrix XenApp to version 6.5 HRP07 or 7.9 (and XenDesktop to 7.9) or later to obtain the security patches that address this memory permission weakness.

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
XenappApplication
Affected:= 6.0.0.0= 6.5.0.0= 7.0.0.0= 7.1.0.0= 7.5.0.0= 7.6.0.0= 7.7.0.0= 7.8.0.0
XendesktopApplication
Affected:<= 7.8

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/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 checks

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

  1. Identify installed Citrix XenApp version
    Open Windows Registry and navigate to HKLM\SOFTWARE\Citrix\XenApp\Version or run 'wmic product where "name like '%XenApp%'" get version' in Command Prompt
    Affected if The reported version is 6.0.0.0, 6.5.0.0, 7.0.0.0, 7.1.0.0, 7.5.0.0, 7.6.0.0, 7.7.0.0, or 7.8.0.0, or any version below 6.5 HRP07 for XenApp 6.x or below 7.9 for XenApp 7.x
  2. Identify installed Citrix XenDesktop version
    Open Windows Registry and navigate to HKLM\SOFTWARE\Citrix\XenDesktop\Version or run 'wmic product where "name like '%XenDesktop%'" get version' in Command Prompt
    Affected if The reported version is 7.8 or any version lower than 7.9
  3. Confirm product is actively running
    Check if the Citrix XenApp or XenDesktop service is running by opening Services.msc and looking for 'Citrix' services, or run 'sc query' for Citrix-related services
    Affected if Any Citrix XenApp version below 6.5 HRP07 (for 6.x) or below 7.9 (for 7.x), or XenDesktop below 7.9, is actively running on the system
  4. Check product build details via PowerShell
    Run 'Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -match "Citrix"} | Select-Object Name, Version' in PowerShell to list all Citrix components
    Affected if Any installed Citrix component matches the affected version ranges listed above

A system is affected if Citrix XenApp version 6.x is below 6.5 HRP07, XenApp 7.x is below 7.9, or XenDesktop is below 7.9, and the product is installed and running.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 7.8
Interim mitigation

Upgrade Citrix XenApp to version 6.5 HRP07 or 7.9 (and XenDesktop to 7.9) or later to obtain the security patches that address this memory permission weakness.

Recommended fix High confidence

XenApp 6.5 HRP07; XenApp 7.9; XenDesktop 7.9

  1. For XenApp 6.x deployments: Upgrade to XenApp 6.5 with Hotfix Rollup Pack 7 (HRP07) or later
  2. For XenApp 7.x deployments (7.0 through 7.8): Upgrade to XenApp 7.9 or later
  3. For XenDesktop deployments (all versions through 7.8): Upgrade to XenDesktop 7.9 or later
  4. After upgrading, verify the security mitigation is properly applied by reviewing Citrix documentation for the memory protection features in the fixed versions
Caveat Review Citrix compatibility guides before upgrading, as newer versions may have dependencies or feature changes that require application testing

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Xenapp Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2016-6493 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