CVE-2021-31188

Information disclosure via Font Entry use-after-free

Published May 11, 2021 · Updated Aug 3, 2024

Use-after-free in Windows Font Entry handling allows local users to disclose sensitive information from system memory. The graphics component operates on a Font Entry object without first validating that the object still exists. Low-privileged code execution is required, and the disclosure can support a separate exploit chain that runs code as SYSTEM.

CVSS severity7.8
High
EPSS probability1.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Windows Font Entry handling allows local users to disclose sensitive information from system memory. The graphics component operates on a Font Entry object without first validating that the object still exists. Low-privileged code execution is required, and the disclosure can support a separate exploit chain that runs code as SYSTEM.

The record

CVE
CVE-2021-31188
Published
May 11, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0 <10.0.10240.18931

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.0 <10.0.10240.18931
Microsoft · Windows Server 2019version=10.0.0 <10.0.17763.1935
Microsoft · Windows 7version=6.1.0 <6.1.7601.24597; version=6.1.0 <6.1.7601.24598
Microsoft · Windows 10 Version 1909version=10.0.0 <10.0.18363.1556
Microsoft · Windows 10 Version 1803version=10.0.0 <10.0.17134.2207
Microsoft · Windows 8.1version=6.3.0 <6.3.9600.20017
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.0 <10.0.14393.4401
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.0 <6.2.9200.23347
Microsoft · Windows Server 2012version=6.2.0 <6.2.9200.23347
Microsoft · Windows Server, version 2004version=10.0.0 <10.0.19041.982
Microsoft · Windows Server 2016version=10.0.0 <10.0.14393.4401
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.0 <6.1.7601.24597; version=6.1.0 <6.1.7601.24598
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.982
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.0.0 <6.1.7601.24597; version=6.0.0 <6.1.7601.24598
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.0 <6.3.9600.20017
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <10.0.17763.1935
Microsoft · Windows 7 Service Pack 1version=6.1.0 <6.1.7601.24597; version=6.1.0 <6.1.7601.24598
Microsoft · Windows Server version 20H2version=10.0.0 <10.0.19042.982
Microsoft · Windows 10 Version 1607version=10.0.0 <10.0.14393.4401
Microsoft · Windows Server 2008 Service Pack 2version=6.0.0 <6.0.6003.21117
Microsoft · Windows 10 Version 2004version=10.0.0 <10.0.19041.982
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.1935
Microsoft · Windows Server 2012 R2version=6.3.0 <6.3.9600.20017
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.0 <6.0.6003.21117
Microsoft · Windows Server, version 1909 (Server Core installation)version=10.0.0 <10.0.18363.1556

Published CVSS scores

2.1NISTAV:L/AC:L/Au:N/C:P/I:N/A:N
5.5NISTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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

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Your stack

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