CVE-2021-22955

HIGH

7.5

CVSS Score

Published: December 7, 2021 at 01:12 PM UTC

Updated: June 17, 2026 at 03:38 AM UTC

3 products affected across 1 vendorGatewayApplication Delivery Controller FirmwareApplication Delivery Controller

Using Citrix ADC, Citrix Gateway by N/A?

Get instant alerts when new vulnerabilities affect Citrix ADC, Citrix Gateway - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

HIGH7.5

Exploit prediction

EPSS 0.9%

Description

A unauthenticated denial of service vulnerability exists in Citrix ADC <13.0-83.27, <12.1-63.22 and 11.1-65.23 when configured as a VPN (Gateway) or AAA virtual server could allow an attacker to cause a temporary disruption of the Management GUI, Nitro API, and RPC communication.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Application Delivery Controller Firmware · Citrix

95%

v ≤ 11.1-65.2312.1 ≤ v < 12.1-63.2213.0 ≤ v < 13.0-83.27

Affected range stops below 12.1-63.22, so it looks safe — our inference, not a vendor statement

Affected range stops below 13.0-83.27, so it looks safe — our inference, not a vendor statement

citrix-application-delivery-controller (same device)

Gateway · Citrix

95%

v < 11.1-65.2312.1 ≤ v < 12.1-63.2213.0 ≤ v < 13.0-83.27Citrix ADC 111.1, 2.1, 13.0,13.1

Affected range stops below 11.1-65.23, so it looks safe — our inference, not a vendor statement

Affected range stops below 12.1-63.22, so it looks safe — our inference, not a vendor statement

Affected range stops below 13.0-83.27, so it looks safe — our inference, not a vendor statement

Application Delivery Controller · Citrix

60%

Citrix ADC 111.1, 2.1, 13.0,13.1

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://support.citrix.com/article/CTX330728

References (1)

x_refsource_MISCVendor Advisory

Source: [email protected]

https://support.citrix.com/article/CTX330728

CVSS

7.5HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-400

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create account Sign in

Free plan, no card