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Vulnerabilities

Vulnerability · CVE-2021-22919

A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP E…

Published Aug 5, 2021 · catalog updated Jun 17, 2026 · application delivery controller firmware

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-22919. EPSS is 0.94%. Act only if a listed version of application delivery controller firmware is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.94%
Remediation
Version ranges on file
Affected products
cpe citrix/application delivery controller firmware · cpe citrix/gateway

A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could lead to the limited available disk space on the appliances being fully consumed.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe citrix/application delivery controller firmware< 11.1-65.22
  • cpe citrix/application delivery controller firmware< 12.1-55.238
  • cpe citrix/application delivery controller firmware< 12.1-62.27
  • cpe citrix/application delivery controller firmware< 13.0-82.45
  • cpe citrix/gateway< 12.1-62.27
  • cpe citrix/gateway< 13.0-82.45

How to fix CVE-2021-22919

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-22919. EPSS is 0.94%. Act only if a listed version of application delivery controller firmware is installed.

Which versions are affected?

Compare what you have installed with citrix/application delivery controller firmware < 11.1-65.22; citrix/application delivery controller firmware < 12.1-55.238; citrix/application delivery controller firmware < 12.1-62.27; citrix/application delivery controller firmware < 13.0-82.45. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.94%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Citrix NetScaler ADC / Gateway security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 5, 2021 · Monitored products — critical

    Detected

    A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could lead to the limited available disk space on the appliances being fully consumed.

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could lead to the limited available disk space on the appliances being fully consumed.

Sources

  • CVE.orgVulnerability recordCVE-2021-22919

    Official CVE identifier

    cve.org
  • Monitored products — criticalVendor advisoryCVE-2021-22919

    A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could lead to the limited available disk space on the appliances being fully consumed.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 8, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 2, 2026