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CVE-2021-34527

Windows Print Spooler Remote Code Execution Vulnerability

CVSS 3.1 High 8.8Known exploited (CISA KEV)

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

Description

A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. UPDATE July 7, 2021: The security update for Windows Server 2012, Windows Server 2016 and Windows 10, Version 1607 have been released. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. In addition to installing the updates, in order to secure your system, you must confirm that the following registry settings are set to 0 (zero) or are not defined (Note: These registry keys do not exist by default, and therefore are already at the secure setting.), also that your Group Policy setting are correct (see FAQ): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint NoWarningNoElevationOnInstall = 0 (DWORD) or not defined (default setting) UpdatePromptSettings = 0 (DWORD) or not defined (default setting) Having NoWarningNoElevationOnInstall set to 1 makes your system vulnerable by design. UPDATE July 6, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. See also KB5005010: Restricting installation of new printer drivers after applying the July 6, 2021 updates. Note that the security updates released on and after July 6, 2021 contain protections for CVE-2021-1675 and the additional remote code execution exploit in the Windows Print Spooler service known as “PrintNightmare”, documented in CVE-2021-34527.

Official description from the CVE record, published by microsoft. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org

Key data

CVSS 3.1 High 8.8

Score published by microsoft in the CVE record.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

  • Attack vector: Network

    The vulnerable component can be reached over a network, possibly from the Internet.

  • Attack complexity: Low

    No special conditions are needed. The attack can be repeated at will.

  • Privileges required: Low

    A basic user account is needed.

  • User interaction: None

    No action from any user is needed.

  • Scope: Unchanged

    The impact stays within the vulnerable component.

  • Confidentiality impact: High

    Serious or total effect on the secrecy of data.

  • Integrity impact: High

    Serious or total effect on the trustworthiness of data.

  • Availability impact: High

    Serious or total effect on availability.

CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.

EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.
Score
0.99792 (99.8% probability)
Percentile
99.95%
Scores of
Nov 10, 2026
Model
v2026.06.15

CISA Known Exploited Vulnerabilities

This CVE is listed in the CISA KEV catalog.
Name in the catalog
Microsoft Windows Print Spooler Remote Code Execution Vulnerability
Added to the catalog
Nov 3, 2021
Federal due date
May 3, 2022
Ransomware campaigns
Known use

CISA assessment as of Jan 24, 2024

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.
Exploitation
Recorded by CISA as active
Automatable
no
Technical impact
total

Affected products

Products listed in the CVE record, as the CNA published them.

  • Microsoft Windows 10 Version 1507

    • affected: 10.0.10240.0 up to before 10.0.10240.18969

  • Microsoft Windows 10 Version 1607

    • affected: 10.0.14393.0 up to before 10.0.14393.4470

  • Microsoft Windows 10 Version 1809

    • affected: 10.0.17763.0 up to before 10.0.17763.2029

  • Microsoft Windows 10 Version 1809

    • affected: 10.0.0 up to before 10.0.17763.2029

  • Microsoft Windows 10 Version 20H2

    • affected: 10.0.0 up to before 10.0.19042.1083

  • Microsoft Windows 10 Version 21H2

    • affected: 10.0.19044.0 up to before 10.0.19044.1415

  • Microsoft Windows 10 Version 22H2

    • affected: 10.0.19045.0 up to before 10.0.19045.2251

  • Microsoft Windows 11 version 21H2

    • affected: 10.0.22000.0 up to before 10.0.22000.318

  • Microsoft Windows 11 version 22H2

    • affected: 10.0.22621.0 up to before 10.0.22621.674

  • Microsoft Windows 8.1

    • affected: 6.3.0 up to before 6.3.9600.20046

  • Microsoft Windows Server 2008 R2 Service Pack 1

    • affected: 6.1.7601.0 up to before 6.1.7601.25633

  • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)

    • affected: 6.1.7601.0 up to before 6.1.7601.25633

  • Microsoft Windows Server 2008 Service Pack 2

    • affected: 6.0.6003.0 up to before 6.0.6003.21138

  • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)

    • affected: 6.0.6003.0 up to before 6.0.6003.21138

  • Microsoft Windows Server 2012

    • affected: 6.2.9200.0 up to before 6.2.9200.23383

  • Microsoft Windows Server 2012 (Server Core installation)

    • affected: 6.2.9200.0 up to before 6.2.9200.23383

  • Microsoft Windows Server 2012 R2

    • affected: 6.3.9600.0 up to before 6.3.9600.20046

  • Microsoft Windows Server 2012 R2 (Server Core installation)

    • affected: 6.3.9600.0 up to before 6.3.9600.20046

  • Microsoft Windows Server 2016

    • affected: 10.0.14393.0 up to before 10.0.14393.4470

  • Microsoft Windows Server 2016 (Server Core installation)

    • affected: 10.0.14393.0 up to before 10.0.14393.4470

  • Microsoft Windows Server 2019

    • affected: 10.0.17763.0 up to before 10.0.17763.2029

  • Microsoft Windows Server 2019 (Server Core installation)

    • affected: 10.0.17763.0 up to before 10.0.17763.2029

  • Microsoft Windows Server 2022

    • affected: 10.0.20348.0 up to before 10.0.20348.230

  • Microsoft Windows Server version 20H2

    • affected: 10.0.0 up to before 10.0.19042.1083

References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

Timeline

  1. ID reserved
  2. Record published
  3. Added to CISA KEV
  4. Record last updated

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Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:52 UTC. Sources and licenses