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Vulnerability record · CVE-2021-22956 · published 7 December 2021

CVE-2021-22956: Citrix application delivery controller firmware uncontrolled resource consumption vulnerability

Citrix · Application Delivery Controller Firmware

An uncontrolled resource consumption vulnerability exists in Citrix ADC <13.0-83.27, <12.1-63.22 and 11.1-65.23 that could allow an attacker with access to NSIP or SNIP with management interface access to cause a temporary disruption of the Management GUI, Nitro API, and RPC communication.

7.5 CVSS 3.1 High EPSS 0.89% · top 42.1% CWE-400 · Uncontrolled resource consumption
7.5CVSS 3.1 base score, v2 4.3
0.89%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

An uncontrolled resource consumption vulnerability exists in Citrix ADC <13.0-83.27, <12.1-63.22 and 11.1-65.23 that could allow an attacker with access to NSIP or SNIP with management interface access to cause a temporary disruption of the Management GUI, Nitro API, and RPC communication.

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

Affected products

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

References

LinkTags
https://support.citrix.com/article/CTX330728 Vendor Advisory
https://support.citrix.com/article/CTX330728 Vendor Advisory

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Related vulnerabilities

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

9.8CVE-2022-27518Citrix ADC and Gateway unauthenticated remote code executionCVE-2022-27518 is an unauthenticated remote arbitrary code execution flaw in Citrix Application Delivery Controller (ADC) and Gateway firmware. The C…KEVEPSS 6.7%analysed9.8CVE-2019-19781Citrix ADC and Gateway directory traversal enabling code executionCitrix Application Delivery Controller (ADC) and Gateway versions 10.5, 11.1, 12.0, 12.1, and 13.0 contain a directory traversal flaw (CWE-22). The t…KEVEPSS 100%analysed9.8CVE-2019-12989Citrix SD-WAN and NetScaler SD-WAN SQL injectionCitrix SD-WAN 10.2.x before 10.2.3 and NetScaler SD-WAN 10.0.x before 10.0.8 are vulnerable to SQL injection. The flaw is remotely reachable without …KEVEPSS 95%analysed8.8CVE-2019-12991Citrix SD-WAN and NetScaler SD-WAN command injection via input validation flawCitrix SD-WAN 10.2.x before 10.2.3 and NetScaler SD-WAN 10.0.x before 10.0.8 fail to properly validate input, allowing OS command injection (CWE-78).…KEVEPSS 74%analysed6.5CVE-2020-8193Citrix ADC and Gateway improper access control allows unauthenticated endpoint accessCitrix ADC, Citrix Gateway, and Citrix SD-WAN WAN-OP contain an improper access control flaw (CWE-284/CWE-287) that lets unauthenticated users reach …KEVEPSS 88%analysed6.5CVE-2020-8195Citrix ADC and Gateway improper input validation information disclosureCitrix ADC, Citrix Gateway, and Citrix SD-WAN WAN-OP contain improper input validation that can result in limited information disclosure to low privi…KEVEPSS 33%analysed4.3CVE-2020-8196Citrix ADC and Gateway improper access control information disclosureCitrix ADC, Citrix Gateway and Citrix SD-WAN WAN-OP appliances contain an improper access control flaw (CWE-284/CWE-287) that allows limited informat…KEVEPSS 26%analysed9.8CVE-2022-27510Citrix gateway authentication bypass via alternate path vulnerabilityUnauthorized access to Gateway user capabilitiesEPSS 1.1%

Source: NIST National Vulnerability Database (record CVE-2021-22956), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.