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    CVE-2021-34527

    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.

    Published:Jul 2, 2021
    Last Modified:Aug 10, 2026
    EPS:Jul 2, 2021
    EPSS Score:0.99759
    CVSS Score:8.8

    CISA Notification

    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.

    Required Action:

    Apply updates per vendor instructions.

    Notes:

    No extra notes provided.

    Due Date
    May 3, 2022
    1592 days ago
    Alert Date
    Nov 3, 2021
    1773 days ago

    Affected Products

    Vendor
    Microsoft
    Product
    Windows 10 1507
    Vendor
    Microsoft
    Product
    Windows 10 1607
    Vendor
    Microsoft
    Product
    Windows 10 1809
    Vendor
    Microsoft
    Product
    Windows 10 20H2
    Vendor
    Microsoft
    Product
    Windows 10 20h2
    Vendor
    Microsoft
    Product
    Windows 10 21H2
    Vendor
    Microsoft
    Product
    Windows 10 21h2
    Vendor
    Microsoft
    Product
    Windows 10 22H2
    Vendor
    Microsoft
    Product
    Windows 10 22h2
    Vendor
    Microsoft
    Product
    Windows 11 21H2
    Vendor
    Microsoft
    Product
    Windows 11 21h2
    Vendor
    Microsoft
    Product
    Windows 11 22H2
    Vendor
    Microsoft
    Product
    Windows 11 22h2
    Vendor
    Microsoft
    Product
    Windows 7
    Vendor
    Microsoft
    Product
    Windows 8.1
    Vendor
    Microsoft
    Product
    Windows Rt 8.1
    Vendor
    Microsoft
    Product
    Windows Server 2008
    Vendor
    Microsoft
    Product
    Windows Server 2008 R2
    Vendor
    Microsoft
    Product
    Windows Server 2008 Sp2
    Vendor
    Microsoft
    Product
    Windows Server 2012
    Vendor
    Microsoft
    Product
    Windows Server 2012 R2
    Vendor
    Microsoft
    Product
    Windows Server 2016
    Vendor
    Microsoft
    Product
    Windows Server 2019
    Vendor
    Microsoft
    Product
    Windows Server 2022
    Vendor
    Microsoft
    Product
    Windows Server 20H2
    Vendor
    Microsoft
    Product
    Windows Server 20h2

    Exploits

    http://packetstormsecurity.com/files/167261/Print-Spooler-Remote-DLL-Injection.htmlhttps://www.vicarius.io/vsociety/posts/cve-2021-34527-printnightmare-detection-scripthttps://www.vicarius.io/vsociety/posts/cve-2021-34527-printnightmare-mitigation-scripthttps://github.com/0xirison/PrintNightmare-Patcherhttps://github.com/AlDawli/CVE-2021-34527-https://github.com/Amaranese/CVE-2021-34527https://github.com/AUSK1LL9/CVE-2021-34527https://github.com/byt3bl33d3r/ItWasAllADreamhttps://github.com/CnOxx1/CVE-2021-34527-1675https://github.com/cyb3rpeace/CVE-2021-34527https://github.com/d0rb/CVE-2021-34527https://github.com/DenizSe/CVE-2021-34527https://github.com/dywhoami/CVE-2021-34527-Scanner-Based-On-cube0x0-POChttps://github.com/Eutectico/Printnightmarehttps://github.com/fengjixuchui/CVE-2021-34527-1675https://github.com/geekbrett/CVE-2021-34527-PrintNightmare-Workaroundhttps://github.com/glorisonlai/printnightmarehttps://github.com/hackerhouse-opensource/cve-2021-34527https://github.com/Hirusha-N/CVE-2021-34527-CVE-2023-38831-and-CVE-2023-32784https://github.com/joertx07/printnightmare-detection-labhttps://github.com/JohnHammond/CVE-2021-34527https://github.com/KaritaMW/printnightmare-detection-mitigation-labhttps://github.com/m8sec/CVE-2021-34527https://github.com/nemo-wq/PrintNightmare-CVE-2021-34527https://github.com/powershellpr0mpt/PrintNightmare-CVE-2021-34527https://github.com/rdboboia/disable-RegisterSpoolerRemoteRpcEndPointhttps://github.com/syntaxbearror/PowerShell-PrintNightmarehttps://github.com/thomas-lauer/PrintNightmarehttps://github.com/TieuLong21Prosper/detect_bruteforcehttps://github.com/Tomparte/PrintNightmarehttps://github.com/twi1ight00/PrintNightmarehttps://github.com/vinaysudheer/Disable-Spooler-Service-PrintNightmare-CVE-2021-34527https://github.com/WidespreadPandemic/CVE-2021-34527_ACL_mitigation

    Common Weakness Enumeration

    No CWE recorded yet

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High