What is CVE-2019-19781?

CVE-2019-19781 is a critical-severity vulnerability in Citrix Application Delivery Controller, classified under Path Traversal. CVSS score: 9.8/10. Published 2019-12-27.

How severe is CVE-2019-19781?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2019-19781 known to be exploited?

Yes. CVE-2019-19781 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 247 public proof-of-concept repositories are indexed.

Path Traversal in Citrix Application Delivery Controller

CVE-2019-19781

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.

Vulnerability class: Path Traversal (Directory Traversal)

Published 2019-12-27 · last modified 2026-08-12.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 1.000 (100.0th percentile), scored 2026-08-18.

Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 100.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Citrix Application Delivery Controller
Citrix Application Delivery Controller Firmware — versions 10.5, 11.1, 12.0
Citrix Gateway
Citrix Gateway Firmware — versions 13.0
Citrix Netscaler Gateway
Citrix Netscaler Gateway Firmware — versions 10.5, 11.1, 12.0

Weakness classification (CWE)

CWE-22 — Path Traversal

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Known ransomware campaign use: yes.

Public proof-of-concept exploits

References

support.citrix.com/article/CTX267027 (Vendor Advisory)
www.kb.cert.org/vuls/id/619785 (US Government Resource, Third Party Advisory, third-party-advisory)
twitter.com/bad_packets/status/1215431625766424576 (Third Party Advisory, Broken Link)
badpackets.net/over-25000-citrix-netscaler-endpoints-vulnerable-to-cve-2019-197… (Third Party Advisory, Broken Link)
forms.gle/eDf3DXZAv96oosfj6 (Third Party Advisory)
packetstormsecurity.com/files/155904/Citrix-Application-Delivery-Controller-Gat… (VDB Entry, Third Party Advisory)
packetstormsecurity.com/files/155930/Citrix-Application-Delivery-Controller-Gat… (VDB Entry, Third Party Advisory)
packetstormsecurity.com/files/155905/Citrix-Application-Delivery-Controller-Gat… (VDB Entry, Third Party Advisory)
packetstormsecurity.com/files/155947/Citrix-ADC-NetScaler-Directory-Traversal-R… (VDB Entry, Third Party Advisory)
packetstormsecurity.com/files/155972/Citrix-ADC-Gateway-Path-Traversal.html (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2019-19781?: CVE-2019-19781 is a critical-severity vulnerability in Citrix Application Delivery Controller, classified under Path Traversal. CVSS score: 9.8/10. Published 2019-12-27.
How severe is CVE-2019-19781?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2019-19781 known to be exploited?: Yes. CVE-2019-19781 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 247 public proof-of-concept repositories are indexed.