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Vulnerability record · CVE-2021-22919 · published 5 August 2021

CVE-2021-22919: Citrix application delivery controller firmware allocation without limits vulnerability

Citrix · Application Delivery Controller Firmware

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.

7.5 CVSS 3.1 High EPSS 0.94% · top 40.4% CWE-770 · Allocation without limits
7.5CVSS 3.1 base score, v2 5.0
0.94%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://support.citrix.com/article/CTX319135 Vendor Advisory
https://support.citrix.com/article/CTX319135 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-22919), CISA KEV, FIRST EPSS (scores of 2026-10-02). This page is refreshed as NVD updates the record.