Exploited CVEs / Citrix / CVE-2019-19781

CVE-2019-19781

Citrix ADC, Gateway, and SD-WAN WANOP Appliance Code Execution Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2022-05-03 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Citrix Security Bulletins, linked below.

Risk summary

CriticalCISA KEVRansomware

9.8

CVSS v3 base

100%

EPSS exploit probability

Critical

Severity

2021-11-03

Added to KEV

2022-05-03 (past due)

CISA due date

Actively exploited Citrix Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance vulnerability, Critical severity, CVSS v3 9.8. Added to the CISA KEV catalog 2021-11-03.

Senserva AI read on CVE-2019-19781 CISA required action Official fix for CVE-2019-19781 Admin questions

Senserva AI Opinion for CVE-2019-19781

Shitrix, the Citrix ADC and Gateway path traversal, is one of the most consequential vulnerabilities of its generation: unauthenticated code execution on the appliance that terminates corporate remote access, EPSS at the 100% maximum, and heavy documented use by ransomware groups and nation-state actors alike. Exploitation outpaced patching so badly in January 2020 that many organizations were compromised before the fix existed. Any ADC, Gateway, or SD-WAN WANOP appliance that ran unpatched should be assumed to have hosted a webshell.

Do this: Confirm every Citrix ADC and Gateway was both patched and forensically checked, since patching alone did not remove implants planted earlier.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2019-19781

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2019-19781, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2019-19781.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed once a day (early morning US Central)):
- CVE-2019-19781: Citrix ADC, Gateway, and SD-WAN WANOP Appliance Code Execution Vulnerability
- Affected: Citrix Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance
- Severity: Critical, CVSS v3 9.8; EPSS 30-day exploitation probability 100%
- Added to CISA KEV: 2021-11-03; federal remediation due 2022-05-03
- Ransomware-linked: YES
- CISA required action: Apply updates per vendor instructions.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch immediately

Exploited in the wild and used in ransomware campaigns.

The fix ships from the vendor: Citrix Security Bulletins.

Do this now: Move this ahead of everything else in the queue, then verify the fix actually landed on every exposed device.

Updated September 3, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2019-19781

Published: 2021-11-03
Last revised: 2021-11-03
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2021-11-03 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 100.0%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2022-05-03 (past due).

Apply updates per vendor instructions.

Official fix for CVE-2019-19781

The authoritative fix and affected-version list are published by the vendor. Find the Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance advisory on Citrix Security Bulletins.

Citrix Security Bulletins CISA KEV entry

Common questions about CVE-2019-19781

Is CVE-2019-19781 actively exploited?

Yes. CVE-2019-19781 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 100%. CISA also reports it is known to be used in ransomware campaigns.

What is the CISA deadline and required action for CVE-2019-19781?

CISA set the federal (BOD 22-01) remediation due date at 2022-05-03, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.

What fixes CVE-2019-19781?

The authoritative fix is in the vendor advisory: see Citrix Security Bulletins for the patched Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2019-19781?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2019-19781's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed once a day (early morning US Central).

Scope and sources

More exploited Citrix CVEs: CVE-2026-8452 CVE-2026-3055 CVE-2025-7775 CVE-2024-8069 CVE-2024-8068 CVE-2025-5777 CVE-2025-6543 CVE-2023-6549
All Citrix exploited CVEs on one page: Citrix vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.