Threats / Citrix / CVE-2019-19781
CVE-2019-19781
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Citrix Application Delivery Controller (ADC), Gateway, and S vulnerability
Citrix ADC, Gateway, and SD-WAN WANOP appliances contain a path traversal vulnerability allowing unauthenticated remote code execution. Actively exploited in ransomware campaigns.
Verdict
Today item, not a backlog item.
Critical remote code execution vulnerability in widely-deployed Citrix infrastructure products. Unauthenticated exploitation, high EPSS score, and confirmed active exploitation in ransomware operations indicate immediate threat to organizations running affected versions.
CISA KEV Yes · 2021-11-034Ransomware use Flagged4EPSS 0.99999 (verify live)5Exploit Weaponized · public PoC6CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
871 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.99999 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: Citrix, Application Delivery Controller (ADC), Gateway, and SD-WAN WANOP Appliance. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-22 Path Traversal — weakness family: Path traversal / file.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 677 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a functional/weaponized public exploit). Catalog entries: Metasploit module, nuclei template. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify a Citrix ADC, Gateway, or SD-WAN WANOP appliance exposed on the network perimeter.
Business
Perimeter security controls fail to prevent reconnaissance of critical infrastructure entry points.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a request exploiting the path traversal flaw to bypass authentication and access restricted functionality.
Business
Authentication mechanisms are circumvented, eliminating a primary security boundary.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute arbitrary code on the appliance with system privileges, establishing persistent access.
Business
Attackers gain control of infrastructure handling sensitive traffic and user sessions.
4
Data at risk — exfiltration narrative 4
Attacker
I deploy ransomware or lateral movement tools to compromise internal networks and data stores.
Business
Operations halt, data is encrypted or exfiltrated, and recovery costs escalate rapidly.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05