PT-2021-5224 · Citrix · Citrix Adc

Published 2021-10-09 · Updated 2025-09-05 · CVE-2021-22956

Positive Technologies (AI Summary)

CVSS v2.0

7.8

High

Base vector

AV:N/AC:L/Au:N/C:N/I:N/A:C

Name of the Vulnerable Software and Affected Versions Citrix ADC versions prior to 13.0-83.27 Citrix ADC versions prior to 12.1-63.22 Citrix ADC version 11.1-65.23

Description An uncontrolled resource consumption issue exists 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. The vulnerability may be exploited by a remote attacker to cause a denial of service on devices.

Recommendations For Citrix ADC versions prior to 13.0-83.27, update to version 13.0-83.27 or later. For Citrix ADC versions prior to 12.1-63.22, update to version 12.1-63.22 or later. For Citrix ADC version 11.1-65.23, consider disabling the management interface access to minimize the risk of exploitation until a patch is available.

Fix

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

BDU:2021-06026

CVE-2021-22956

Affected Products

Citrix Adc

References · 7

• https://nvd.nist.gov/vuln/detail/CVE-2021-22956 · Security Note
• https://support.citrix.com/article/CTX330728 · Vendor Advisory
• https://bdu.fstec.ru/vul/2021-06026 · Security Note
• https://osv.dev/vulnerability/CVE-2021-22956 · Vendor Advisory
• https://reddit.com/r/Citrix/comments/1n978y7/netscaler_maxclients_cve202122956_security · Reddit Post
• https://t.me/isacarusec/4653 · Telegram Post
• https://t.me/true_secator/2312 · Telegram Post