Medium severity · published Aug 5, 2021
CVE-2021-22920
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…
6.5
CVSS
0.9%
EPSS
No
On KEV
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 a phishing attack through a SAML authentication hijack to steal a valid user session.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 60% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NA
NetScaler ADC · Citrix
12.1-62.25; 13.0-82.42 · source: NVD
AD
Application Delivery Management · Citrix
12.1-62.25; 13.0-82.42 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-22920
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-22920
Vendor Advisory
https://support.citrix.com/article/CTX319135
More from NetScaler ADC
9.8
CVE-2026-88771
A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands
9.8
CVE-2026-19490
NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2026-19490
9.8
CVE-2026-8452
Memory overflow vulnerability leading to unpredictable or erroneous behavior and Denial of Service
9.8
CVE-2026-3055
Insufficient input validation leading to memory overread
9.8
CVE-2025-7775
Memory overflow vulnerability leading to Remote Code Execution and/or Denial of Service