Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-88771 – Unauthenticated Remote Code Execution – Citrix NetScaler ADC and Gateway (before 14

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-88771 is a critical improper input validation vulnerability (CWE-20) in Citrix NetScaler ADC and NetScaler Gateway that allows an unauthenticated, remote attacker to execute arbitrary commands on the appliance. Citrix has confirmed active exploitation of this flaw in the wild against unmitigated deployments. The vulnerability affects all NetScaler ADC and Gateway configurations by default, with no optional feature required for exposure, and carries a CVSS score of 9.5 (Critical).

Technical details

  • Root cause: Improper input validation (CWE-20) in the NetScaler ADC/Gateway management or traffic-handling code path.
  • Trigger conditions: No authentication or special configuration is required; the flaw affects default NetScaler ADC and Gateway deployments out of the box.
  • Attack vector: Network-based, requiring only network access to the exposed NetScaler management or gateway interface — no user interaction and no prior authentication needed.
  • Impact: Successful exploitation allows an unauthenticated attacker to execute arbitrary commands on the appliance, potentially leading to full compromise of the device and the network traffic it brokers (VPN, load balancing, authentication).
  • Exploitation status: Citrix has stated that exploitation of CVE-2026-88771 has been observed on unmitigated NetScaler deployments; the vulnerability was reportedly exploited as a zero-day prior to public disclosure of a patch.

Affected software

  • Citrix NetScaler ADC: versions before 14.1-73.37
  • Citrix NetScaler ADC: versions before 13.1-64.23
  • Citrix NetScaler ADC 14.1-FIPS: versions before 14.1-73.37 FIPS
  • Citrix NetScaler ADC 13.1-FIPS and 13.1-NDcPP: versions before 13.1-37.279
  • Citrix NetScaler Gateway: versions before 14.1-73.37
  • Citrix NetScaler Gateway: versions before 13.1-64.23

Severity

  • CVSS Score: 9.5 (Critical)
  • Note: Citrix has published this score using the CVSS v4.0 framework (vector: AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H). No equivalent CVSS v3.1 vector has been published by the vendor or NVD at the time of writing.

Mitigation and recommended actions

  • Immediate: Upgrade to the patched builds: NetScaler ADC and Gateway 14.1-73.37 or later; 13.1-64.23 or later; NetScaler ADC 14.1-FIPS 14.1-73.37 FIPS or later; NetScaler ADC 13.1-FIPS/13.1-NDcPP 13.1-37.279 or later.
  • If patching cannot be completed immediately: Citrix has not published a workaround for this vulnerability — patching is the only mitigation. Restrict network exposure of NetScaler management interfaces and VPN/gateway virtual servers where possible until upgrades are applied.
  • Review NetScaler Console’s Security Advisory workflow (available with Console/Cloud Connect telemetry from version 14.1-73.36) for indicators of compromise, and forward appliance logs to an external SIEM.
  • Where suspicious activity is identified, preserve evidence and engage forensic responders, as Citrix has cautioned that available checks may not detect every exploitation technique.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge