CVE-2019-19781 — Application Delivery Controller Firmware
CRITICALCVE-2019-19781 is a critical-severity (CVSS 9.8) Path Traversal vulnerability in citrix application delivery controller firmware. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) and has been used in ransomware campaigns — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
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.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2021-11-03 — including use in ransomware campaigns. Federal agencies were required to remediate by 2022-05-03.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2019-19781.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2019-19781 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
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.
Affected Products
application delivery controller firmwarecitrixgateway firmwarecitrixnetscaler gateway firmwarecitrixResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Citrix Application Delivery Controller and Gateway 10.5 - Remote Code Execution (Metasploit)
by mekhalleh · Jan 13, 2020
Citrix Application Delivery Controller (ADC) and Gateway 13.0 - Path Traversal
by Dhiraj Mishra · Jan 16, 2020
Citrix Application Delivery Controller and Citrix Gateway - Remote Code Execution (PoC)
by Project Zero India · Jan 11, 2020
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every citrix application delivery controller firmware deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2019-19781 yet — track the citrix application delivery controller firmware advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
How to detect CVE-2019-19781
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2019-19781 -u https://target- Template
- Citrix ADC and Gateway - Directory Traversal
- Severity
- critical
- Impact
- Successful exploitation of this vulnerability can lead to unauthorized access to sensitive information, potential data leakage, and further compromise of the affected system.
- Remediation
- Apply the necessary security patches provided by Citrix to fix the directory traversal vulnerability.
Template by ProjectDiscovery nuclei-templates (organiccrap, geeknik), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2019-19781 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.