+44 1865 950 828 Secure Your Business
Actively exploitedKnown ransomware use

CVE-2019-19781 Citrix ADC, Gateway, and SD-WAN WANOP Appliance Code Execution Vulnerability

Citrix ADC, Citrix Gateway, and multiple Citrix SD-WAN WANOP appliance models contain an unspecified vulnerability that could allow an unauthenticated attacker to perform code execution.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 3 Nov 2021.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated Critical severity (CVSS 9.8, scored by CISA).
  • This product type is often exposed to the internet, which is where attackers scan for it first.
  • Named in Cybergen threat actor reporting: APT29.
  • It has been in the catalogue for 1,829 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

An issue was discovered in Citrix Application Delivery Controller (ADC) and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0. They allow Directory Traversal.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Citrix Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 3 May 2022 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Citrix Flaws

Get alerts for CitrixWe email you when a new Citrix vulnerability is confirmed as exploited. Add more vendors on Threat Watch.

By signing up you agree to receive Threat Watch alerts. Unsubscribe at any time. See our Privacy Policy.

CVE-2026-88779Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer VulnerabilityAdded 4 Oct 2026CVE-2026-88772Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer VulnerabilityAdded 27 Sep 2026CVE-2026-88771Citrix NetScaler Improper Input Validation VulnerabilityAdded 27 Sep 2026CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel VulnerabilityAdded 9 Sep 2026CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer VulnerabilityAdded 26 Aug 2026CVE-2026-3055Citrix NetScaler Out-of-Bounds Read VulnerabilityAdded 30 Mar 2026

All 27 exploited Citrix vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2019-19781 and every other exploited flaw on the list.

Check My Exposure
Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2019-19781
  3. CVE record: CVE-2019-19781
  4. FIRST EPSS
  5. support.citrix.com/article/CTX267027
  6. kb.cert.org/vuls/id/619785
  7. twitter.com/bad_packets/status/1215431625766424576
  8. badpackets.net/over-25000-citrix-netscaler-endpoints-vulnerable-to-cve-2019-19781/
  9. forms.gle/eDf3DXZAv96oosfj6
  10. packetstormsecurity.com/files/155904/Citrix-Application-Delivery-Controller-Gateway-Remote-Code-Exec
  11. packetstormsecurity.com/files/155930/Citrix-Application-Delivery-Controller-Gateway-10.5-Remote-Code
  12. packetstormsecurity.com/files/155905/Citrix-Application-Delivery-Controller-Gateway-Remote-Code-Exec