Citrix Workspace Application and Receiver for Windows Remote Code Execution Vulnerability

Citrix Workspace App before 1904 for Windows has Incorrect Access Control.

CheckOps priority index

6.6/10 Patch within 7 days

Severity9.8

Probability0.8

Exploitation4/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 8.1% higher than 94.8% of CVEs

CVSS 3.1 9.8 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:

Exploited for 1,826 days 03 Nov 2021

CISA due date 03 May 2022 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 4 / 5

KEV catalog (CISA)03 Nov 2021
Exploited in EUVD (ENISA)03 Nov 2021
Used by ransomwareyes
EPSS above 10 %8.1%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Workspace Application and Receiver for Windows

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

22 May 2019
Published
03 Nov 2021
Exploitation reported (ENISA)
03 Nov 2021
Added to the KEV catalog
03 May 2022
CISA remediation due date

References

Other exploited vulnerabilities from the same vendor

CVE-2026-88779Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
6.2 · Actively exploited
CVE-2026-88772Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
8.5 · Actively exploited
CVE-2026-88771Citrix NetScaler Improper Input Validation Vulnerability
8.7 · Actively exploited
CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
7.1 · Actively exploited
CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
5.4 · Actively exploited
CVE-2026-3055Citrix NetScaler Out-of-Bounds Read Vulnerability
8.9 · Background exploitation