CVE-2021-21987

Information disclosure via ThinPrint font buffer over-read

Published May 24, 2021 · Updated Aug 3, 2024

Out-of-bounds read in VMware Workstation 16.x before 16.1.2 and Horizon Client 5.x before 5.5.2 allows guest OS users to read TPView memory. The Cortado ThinPrint TTC parser accepts crafted font data and reads past the end of an allocated buffer. Exploitation requires virtual printing and access to a guest VM or remote desktop; the direct consequence is disclosure of TPView process memory.

CVSS severity3.2
Low
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds read in VMware Workstation 16.x before 16.1.2 and Horizon Client 5.x before 5.5.2 allows guest OS users to read TPView memory. The Cortado ThinPrint TTC parser accepts crafted font data and reads past the end of an allocated buffer. Exploitation requires virtual printing and access to a guest VM or remote desktop; the direct consequence is disclosure of TPView process memory.

The record

CVE
CVE-2021-21987
Published
May 24, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1005
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N
3.2VMwareCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
6.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo