CVE-2021-34527

highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.998 · 100 %ileexploit · functionalDEEURUUS
grimoire priorityP0 · Act now
Exploitable?
Yes · in the wild
CISA KEV · 30 exploits · functional
Likely / severe?
99.8% (100th) EPSS
CVSS 9 · high
Is it mine?
145 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · pepperl_fuchs_psirt

added 2021-11-03remediate by 2022-05-03

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-27

Microsoft Windows Print Spooler Remote Code Execution Vulnerability

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

9.0
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.09highAV:N/AC:L/Au:S/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8 · impact 10
v2.09highAV:N/AC:L/Au:S/C:C/I:C/A:C/E:Hsecondary · CVSS-BT (t0sche)
v3.18.8highAV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:Csecondary · ENISA EU
v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · secure@microsoft.com USexploitability 2.8 · impact 5.9
v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · Pepperl+Fuchs PSIRT DE
v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:Csecondary · Microsoft Security Response Center US
v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · NVD / NIST USexploitability 2.8 · impact 5.9
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-264USCWE-269US
05

exploits (30)

Public proof-of-concept and weaponised exploit code.

06

affected products (145)

Products and version ranges known to be affected.

showing 20 of 145
07

advisories (2)

Vendor and ecosystem advisories describing this.

  • VDE-2021-034Pepperl+Fuchs: Security Advisory for PrintNightmare Vulnerability in multiple HMI Devices2021-07-30csaf · pepperl_fuchs_psirtDE

    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. See details on Microsoft Advisory CVE-2021-34527 (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34527)

  • msrc_CVE-2021-34527Windows Print Spooler Remote Code Execution Vulnerability2021-07-01csaf · msrc_csafUS

    To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

08

also known as (4)

Other names and identifiers for this entity.

09

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bdupepperl_fuchs_psirtmsrc_csafNVDCVE.orgMITRE
published 2021-07-02modified 2026-08-10
10

references (18)

External citations — patches, advisories, analysis.

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