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Threats / Citrix / CVE-2019-11634
CVE-2019-11634 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

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 · 2021-11-033Ransomware use Flagged3EPSS 0.08091 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported 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.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.08091 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Citrix, Workspace Application and Receiver for Windows. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution 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 board
1

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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • 6 reported-exploitation source(s)
  • Catalogued by mitre (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by mitreCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.