CVE-2020-1021

Local privilege escalation via file-handling race

Published May 21, 2020 · Updated Aug 19, 2026

Windows Error Reporting in affected Windows 10 and Windows Server releases allows local users to elevate privileges via a crafted application. A race condition occurs while WER handles and executes files, but Microsoft has not disclosed the specific file operation or synchronization failure. Existing low-privilege code execution is required; successful exploitation grants broader access to sensitive information and system functionality.

CVSS severity7.8
High
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Windows Error Reporting in affected Windows 10 and Windows Server releases allows local users to elevate privileges via a crafted application. A race condition occurs while WER handles and executes files, but Microsoft has not disclosed the specific file operation or synchronization failure. Existing low-privilege code execution is required; successful exploitation grants broader access to sensitive information and system functionality.

The record

CVE
CVE-2020-1021
Published
May 21, 2020
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
CWE-362, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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=10.0.10240.0 <publication

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.10240.0 <publication
Microsoft · Windows Server 2019version=10.0.17763.0 <publication
Microsoft · Windows 10 Version 1909version=10.0.0 <publication
Microsoft · Windows 10 Version 1803version=10.0.0 <publication
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <publication
Microsoft · Windows Server 2016version=10.0.14393.0 <publication
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <publication
Microsoft · Windows Server, version 1903 (Server Core installation)version=10.0.0 <publication
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <publication
Microsoft · Windows Server, version 1803 (Server Core installation)version=10.0.0 <publication
Microsoft · Windows 10 Version 1709version=10.0.0 <publication
Microsoft · Windows 10 Version 1809version=10.0.0 <publication; version=10.0.17763.0 <publication
Microsoft · Windows Server, version 1909 (Server Core installation)version=10.0.0 <publication
Microsoft · Windows 10 Version 1903version=10.0.0 <publication

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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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