dbcve.org
Application Delivery ManagementApplication · Citrix

CVE-2021-22920

MEDIUM · 6.5 CVSS v3.1 Published 2021-08-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A SAML authentication vulnerability in Citrix ADC, Citrix Gateway, and Citrix SD-WAN WANOP Edition allows attackers to hijack valid user sessions through phishing attacks. The flaw enables stealing authenticated sessions, likely due to improper validation of SAML assertions or session tokens.

MitigationApply vendor patches for CVE-2021-22920 to affected Citrix ADC, Citrix Gateway, and SD-WAN WANOP deployments. Review SAML configuration for anomalies and monitor for suspicious session activity.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Application Delivery ManagementApplication
Affected:= 12.1-62.25= 13.0-82.42
GatewayApplication
Affected:= 12.1-62.25= 13.0-82.42

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Citrix product and installed version
    Run 'nsversion' from the Citrix ADC CLI or check System > Information in the GUI to determine the exact build number and version (12.1 or 13.0)
    Affected if The version matches 12.1 build 62.25 or 13.0 build 82.42 exactly, or falls within the 12.1-62.25 or 13.0-82.42 range (meaning the build number is equal to or lower than 62.25 for 12.1, or equal to or lower than 82.42 for 13.0)
  2. Confirm SAML authentication is configured
    Run 'show aaa' or 'show authentication saml' from the CLI, or navigate to AAA > Authentication > SAML in the GUI to verify if SAML IdP is bound to the virtual server
    Affected if SAML authentication is enabled and an IdP is configured (the vulnerability only affects systems using SAML for authentication)
  3. Check for SAML IdP certificate or metadata changes
    Run 'show samlIdPProfile' and compare the currently configured IdP metadata fingerprint or certificate against the known legitimate IdP configuration in your documentation
    Affected if The IdP metadata or certificate has been changed or does not match your documented configuration, indicating potential tampering
  4. Review active session bindings for anomalies
    Run 'show session' or 'show aaa session' to list active authenticated sessions and check for unexpected source IP addresses or session parameters
    Affected if Active sessions exist from unfamiliar IP addresses or show anomalous binding attributes that do not match legitimate user patterns

The environment is affected if the Citrix ADC or Gateway version is 12.1 up to build 62.25 or 13.0 up to build 82.42 AND SAML authentication is actively configured for user access.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patches for CVE-2021-22920 to affected Citrix ADC, Citrix Gateway, and SD-WAN WANOP deployments. Review SAML configuration for anomalies and monitor for suspicious session activity.

Fix this in Application Delivery Management Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-22920 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-22920 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data