CVE-2019-19781Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via traversal and template injection

Published Dec 27, 2019 · Updated Aug 12, 2026

Path traversal in Citrix ADC and Gateway portal handling allows remote attackers to execute code via crafted HTTP requests. UserPrefs.pm builds XML file paths from unsanitized NSC_USER headers, and Handler.pm renders attacker-controlled XML as executable template directives. Exploitation requires network access to an affected portal or management endpoint but no credentials or user interaction, and grants control of the appliance.

CVSS severity9.8
Critical
EPSS probability100.00%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Contact us

Summary

What happened

Path traversal in Citrix ADC and Gateway portal handling allows remote attackers to execute code via crafted HTTP requests. UserPrefs.pm builds XML file paths from unsanitized NSC_USER headers, and Handler.pm renders attacker-controlled XML as executable template directives. Exploitation requires network access to an affected portal or management endpoint but no credentials or user interaction, and grants control of the appliance.

The record

CVE
CVE-2019-19781
Published
Dec 27, 2019
Updated
Aug 12, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 27, 2019CVE publishedPublication date reported by the CVE source.
  2. Jan 12, 2020Exploitation reportedTrustedSec NetScaler honeypot compromise
  3. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 202616
Sep 23, 202611
Sep 24, 202613
Sep 25, 202637
Sep 26, 20269
Sep 27, 202623
Sep 28, 202628
Latest reporting daySep 28, 2026
Latest daily unique IPs28
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Contact us