What is the CVSS score of CVE-2019-19781?

CVE-2019-19781 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 94.4%.

Is there a public PoC exploit available for CVE-2019-19781?

Yes, a public proof-of-concept exploit is available for CVE-2019-19781. Prioritise patching immediately. EPSS: 94.4%.

How to fix or mitigate CVE-2019-19781?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Review file handling controls and restrict upload directories.

Netscaler Gateway Firmware CVE-2019-19781

CRITICAL

Path Traversal (CWE-22)

2019-12-27 cve@mitre.org

Path Traversal Citrix Netscaler Gateway Firmware Application Delivery Controller Firmware Gateway Firmware

9.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-22 OWASP Top 10:2025 A01:2021 - Broken Access Control ASVS 5.0 V4 - Access Control Authorization enforcement, RBAC validation MITRE ATT&CK 2 techniques across 2 tactics: Discovery, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	Extreme risk (CVSS 9.8, EPSS 94.4%). Mass exploitation began in January 2020, weeks before Citrix released patches (only mitigation steps were initially available). Healthcare, finance, and government organizations were heavily targeted. Ransomware groups established persistent access on thousands of Citrix appliances.
Exploit ScenarioDerived	Attackers sent crafted requests to vulnerable Citrix appliances to write a Perl reverse shell to a web-accessible directory. Accessing the shell URL triggered execution, providing command-line access. Threat actors then pivoted into internal networks, deployed ransomware, or sold access to other criminal groups.

Emergency Immediate action required. Why: CRITICAL + in CISA KEV (actively exploited), no patch available.

Exploited in the wild (CISA KEV) No patch listed yet 94.4% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 26, 2026

Citrix Application Delivery Controller and Gateway contain a directory traversal vulnerability allowing unauthenticated remote code execution, known as 'Shitrix', that triggered a global exploitation crisis in January 2020.

Earlier versions of this analysis (1)

v1 Mar 26, 2026 - 11:19 CVSS 9.8

A critical directory traversal vulnerability in Citrix ADC and Gateway allows unauthenticated remote code execution. Known as 'Shitrix' for its severity and widespread exploitation, it affected an estimated 80,000 organizations globally.

RemediationAI

Apply Citrix security updates. Verify no backdoors were installed during the exploitation window. Check for unauthorized users, modified configurations, and web shells. Rotate all credentials accessible from the Citrix appliance.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The CWE-22 path traversal in Citrix's NSPPE (Netscaler Perl Extension) allows attackers to write files to arbitrary directories through crafted requests. By writing a Perl template file to the web-accessible cron scripts directory, attackers achieve code execution as the web server user.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Nov 07, 2025 - 19:37 cisa

CISA KEV

PoC Detected

Nov 07, 2025 - 19:37 vuln.today

Public exploit code

CVE Published

Dec 27, 2019 - 14:15 nvd

CRITICAL 9.8

DescriptionNVD

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.

Executive ViewAI

Why It Matters

CVE-2019-19781 presents critical security risk, a path traversal vulnerability rated CVSS 9.8. This could allow attackers to access or modify files outside intended directories, potentially exposing sensitive configuration or credentials. This vulnerability is actively exploited in the wild (KEV-listed) and requires immediate remediation. Immediate patching is required per CISA KEV mandate.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Restrict file upload functionality via WAF; (2) Implement allowlist-based file type validation; (3) Use chroot/containerization to limit filesystem access.

Threat Intelligence Overview

Threat Score

9.8/10

Composite threat intelligence

EPSS Score

94.4%

Top 0% exploitable

Threat Intel

1 sources

Exploit

POC

Public exploit code exists

Data Quality

7 sources

Confidence: High

Citrix

NVD

CVE.org

CISA KEV

EPSS POC (3) THREAT

Exploit-DB

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV Yes

Public POC Yes

EPSS 94.4%

Patch available No

Active threat Yes

Deciding rule

CRITICAL + in CISA KEV (actively exploited), no patch available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Immediate

Exploitation· derived

Active

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

238

Low Medium High Critical

KEV: +50

EPSS: +94

CVSS: +49

PoC: +20

Weaponized: +15

Threat intel: +10

Gov advisory: 0

Attack Technique

Path Traversal HIGH

Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.

Affected Products (CPE)NVD

cpe:2.3:o:citrix:application_delivery_controller_firmware:10.5:*:*:*:*:*:*:*

cpe:2.3:o:citrix:application_delivery_controller_firmware:11.1:*:*:*:*:*:*:*

cpe:2.3:o:citrix:application_delivery_controller_firmware:12.0:*:*:*:*:*:*:*

cpe:2.3:o:citrix:application_delivery_controller_firmware:12.1:*:*:*:*:*:*:*

cpe:2.3:o:citrix:application_delivery_controller_firmware:13.0:*:*:*:*:*:*:*

cpe:2.3:o:citrix:netscaler_gateway_firmware:10.5:*:*:*:*:*:*:*

cpe:2.3:o:citrix:netscaler_gateway_firmware:11.1:*:*:*:*:*:*:*

cpe:2.3:o:citrix:netscaler_gateway_firmware:12.0:*:*:*:*:*:*:*

cpe:2.3:o:citrix:netscaler_gateway_firmware:12.1:*:*:*:*:*:*:*

cpe:2.3:o:citrix:gateway_firmware:13.0:*:*:*:*:*:*:*

More in Netscaler Gateway Firmware

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CVE-2020-8195 MEDIUM This Month POC

6.5 Jul 10

Improper input validation in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.1

CVE-2020-8194 MEDIUM This Month POC

6.5 Jul 10

Reflected code injection in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.14

CVE-2020-8193 MEDIUM This Month POC

6.5 Jul 10

Improper access control in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.14

CVE-2015-5538 CRITICAL Act Now

10.0 Sep 17

Multiple unspecified vulnerabilities in Citrix NetScaler Application Delivery Controller (ADC) and NetScaler Gateway bef

CVE-2020-8191 MEDIUM This Month POC

6.1 Jul 10

Improper input validation in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.1

CVE-2019-18225 CRITICAL Act Now

9.8 Oct 21

An issue was discovered in Citrix Application Delivery Controller (ADC) and Gateway before 10.5 build 70.8, 11.x before

CVE-2018-7218 CRITICAL Act Now

9.8 May 17

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CVE-2018-6809 CRITICAL Act Now

9.8 Mar 06

NetScaler ADC 10.5, 11.0, 11.1, and 12.0, and NetScaler Gateway 10.5, 11.0, 11.1, and 12.0 allow remote attackers to gai

CVE-2015-5080 CRITICAL Act Now

9.0 Jul 16

The Management Interface in Citrix NetScaler Application Delivery Controller (ADC) and NetScaler Gateway 10.1 before 10.

CVE-2017-7219 HIGH This Week

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A heap overflow vulnerability in Citrix NetScaler Gateway versions 10.1 before 135.8/135.12, 10.5 before 65.11, 11.0 bef

CVE-2020-8197 HIGH This Week

8.8 Jul 10

Privilege escalation vulnerability on Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21,

Same weakness CWE-22 – Path Traversal

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CVE-2019-3396 CRITICAL POC

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CVE-2020-5902 CRITICAL POC

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CVE-2021-21972 CRITICAL POC

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CVE-2021-40444 HIGH POC

8.8

CVE-2022-41352 CRITICAL POC

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CVE-2021-27065 HIGH POC

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CVE-2019-11510 CRITICAL POC

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CVE-2022-37042 CRITICAL POC

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Same technique Path Traversal

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CVE-2018-20250 HIGH POC

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CVE-2025-64446 CRITICAL POC

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CVE-2022-30333 HIGH POC

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Threat IntelligenceMISP

Threat Actors

APT41 APT29 Dragonfly

Malware Families

NOTROBIN

ATT&CK Techniques (observed)

T1071.001 - Web Protocols T1190 - Exploit Public-Facing Application

Sources: MITRE ATT&CK, MISP Galaxies (CC0), Metasploit/Nuclei

References

Advisories & patches

ADVISORY https://support.citrix.com/article/CTX267027 ADVISORY https://vuldb.com/vuln/147804 REF http://packetstormsecurity.com/files/155904/Citrix-Application-Delivery-Controller-Gateway-Remote-Code-Execution.html REF http://packetstormsecurity.com/files/155905/Citrix-Application-Delivery-Controller-Gateway-Remote-Code-Execution-Traversal.html REF http://packetstormsecurity.com/files/155930/Citrix-Application-Delivery-Controller-Gateway-10.5-Remote-Code-Execution.html REF http://packetstormsecurity.com/files/155947/Citrix-ADC-NetScaler-Directory-Traversal-Remote-Code-Execution.html REF http://packetstormsecurity.com/files/155972/Citrix-ADC-Gateway-Path-Traversal.html REF https://badpackets.net/over-25000-citrix-netscaler-endpoints-vulnerable-to-cve-2019-19781/ REF https://forms.gle/eDf3DXZAv96oosfj6 REF https://twitter.com/bad_packets/status/1215431625766424576 REF https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-19781 REF https://www.kb.cert.org/vuls/id/619785

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GitHub PoC

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