Threats / Citrix / CVE-2019-11634
CVE-2019-11634
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Citrix Workspace Application and Receiver for Windows vulnerability
Citrix Workspace Application and Receiver for Windows contains a remote code execution vulnerability due to insufficient enforcement of local drive access restrictions, allowing attackers to execute arbitrary code on affected systems.
Verdict
Today item, not a backlog item.
This vulnerability enables remote code execution through improper local drive access controls. Active exploitation and ransomware campaigns have been documented, making it a critical threat to Windows endpoints running affected Citrix client software.
CISA KEV Yes · 2021-11-034Ransomware use Flagged4EPSS 0.08026 (verify live)5CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
6 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 0.08026 — 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, Workspace Application and Receiver for Windows. 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.
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 896 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.
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 exploit the local drive access bypass to write malicious code to the client system.
Business
Endpoints running Citrix clients become compromised entry points for ransomware and data theft operations.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute arbitrary code with the privileges of the Citrix application process.
Business
Attackers gain persistent access to corporate networks and can move laterally to critical systems.
3
Lateral reach — past segmentation narrative 3
Attacker
I deploy ransomware or exfiltration tools across compromised client machines.
Business
Organizations face operational disruption, data loss, and financial extortion from active ransomware campaigns.
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