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GatewayApplication · Citrix

CVE-2020-8299

MEDIUM · 6.5 CVSS v3.1 Published 2021-06-16
Fix available
A fix is available. Upgrade to 10.2.9a / 11.1.2c or later.
See remediation →
70/100
Remediation priority · Elevated
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 ADC and Citrix/NetScaler Gateway 13.0 before 13.0-76.29, 12.1-61.18, 11.1-65.20, Citrix ADC 12.1-FIPS before 12.1-55.238, and Citrix SD-WAN WANOP Edition before 11.4.0, 11.3.2, 11.3.1a, 11.2.3a, 11.1.2c, 10.2.9a suffers from uncontrolled resource consumption by way of a network-based denial-of-service from within the same Layer 2 network segment. Note that the attacker must be in the same Layer 2 network segment as the vulnerable appliance.

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 confidence

Citrix ADC, Citrix/NetScaler Gateway, and Citrix SD-WAN WANOP appliances suffer from an uncontrolled resource consumption vulnerability allowing denial-of-service attacks from attackers within the same Layer 2 network segment. The vulnerability enables a network-based DoS that can exhaust device resources.

MitigationUpgrade to the fixed versions (13.0-76.29, 12.1-61.18, 11.1-65.20, 12.1-55.238, or the specified versions for SD-WAN WANOP). Network segmentation can limit attack surface since the attacker requires Layer 2 adjacency.

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
GatewayApplication
Affected:>= 12.1, < 12.1-61.18>= 13.0, < 13.0-76.29
Netscaler GatewayApplication
Affected:>= 11.1, < 11.1-65.20
Application Delivery Controller FirmwareOperating system
Affected:>= 11.1, < 11.1-65.20>= 12.1, < 12.1-61.18>= 13.0, < 13.0-76.29>= 12.1, < 12.1-55.238
Sd Wan WanopOperating system
Affected:>= 10.2, < 10.2.9a>= 11.1, < 11.1.2c>= 11.2, < 11.2.3a>= 11.3, < 11.3.2

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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 checks

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

  1. Identify the Citrix product type
    Access the device CLI or web interface. Run 'show version' or check the System Information page to determine if the device is Citrix ADC, Citrix Gateway, Netscaler Gateway, or SD-WAN WANOP.
    Affected if The device is any of these product types and the version falls within the vulnerable ranges.
  2. Determine the exact firmware version
    On Citrix ADC/Gateway: run 'nsversion' or 'show build' in the CLI. On SD-WAN WANOP: run 'show software' or check the web interface under Administration > System Administration > System Information.
    Affected if The version number is lower than the fixed releases.
  3. Check if the device is running a vulnerable version range
    Compare the installed version against the affected ranges: Gateway (>=12.1 <12.1-61.18 or >=13.0 <13.0-76.29), Netscaler Gateway (>=11.1 <11.1-65.20), ADC Firmware (>=11.1 <11.1-65.20, >=12.1 <12.1-61.18, >=13.0 <13.0-76.29, or >=12.1 <12.1-55.238), SD-WAN WANOP (>=10.2 <10.2.9a, >=11.1 <11.1.2c, >=11.2 <11.2.3a, or >=11.3 <11.3.2).
    Affected if The installed version falls within any of the listed vulnerable ranges.
  4. Verify network adjacency
    Determine if untrusted hosts can connect to the same Layer 2 network segment as the Citrix device. Check switch port access, VLAN configuration, and whether the management or peer interfaces are exposed to shared network segments.
    Affected if Untrusted or external devices can reach the same Layer 2 segment as the Citrix appliance.

The device is affected if it is a Citrix ADC, Netscaler Gateway, or SD-WAN WANOP appliance running a version below the fixed releases AND is accessible from an attacker's Layer 2 network segment.

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 10.2.9a / 11.1.2c / 11.1-65.20 or later
Fixed in 10.2.9a11.1.2c11.1-65.20
Interim mitigation

Upgrade to the fixed versions (13.0-76.29, 12.1-61.18, 11.1-65.20, 12.1-55.238, or the specified versions for SD-WAN WANOP). Network segmentation can limit attack surface since the attacker requires Layer 2 adjacency.

Fix this in Gateway Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

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

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dbcve dependency scanner

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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-2020-8299 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