CVE-2021-21987

VMware Workstation (16.x prior to 16.1.2) and Horizon Client for Windows (5.x prior to 5.5.2) contain out-of-bounds read vulnerability in the Cortado ThinPrint component (TTC Parser). A malicious actor with access to a virtual machine or remote desktop may be able to exploit these issues leading to information disclosure from the TPView process running on the system where Workstation or Horizon Client for Windows is installed.

Published: 2021-05-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21987 is rated Low Risk (39.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.18%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-21987

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.10% 0.18% +0.07%
2 2025-11-18 0.18% 0.10% -0.07%
3 2025-05-28 — 0.18% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21987

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.0 4.0 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2021-21987

Affected software / configurations for CVE-2021-21987

Vendor Product Version Raw CPE
vmware workstation >= 16.0.0, < 16.1.2 cpe:2.3:a:vmware:workstation:*:*:*:*:*:*:*:*
vmware horizon_client >= 5.0.0, < 5.5.2 cpe:2.3:a:vmware:horizon_client:*:*:*:*:*:*:*:*

References for CVE-2021-21987

cvelogic Threat Intelligence