Detections
Analytics
CVE-2021-34527
high
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.
From the Tenable Blog
CVE-2021-34527: Microsoft Releases Out-of-Band Patch for PrintNightmare Vulnerability in Windows Print Spooler
Published: 2021-07-07
Microsoft issues an out-of-band patch for critical ‘PrintNightmare’ vulnerability following reports of in-the-wild exploitation and publication of multiple proof-of-concept exploit scripts Update July 9, 2021: The Solution section has been updated to clarify the vulnerable configurations as well as a mitigation to ensure exploitation is not feasible post-patch
References
https://securelist.com/vulnerabilities-and-exploits-in-q3-2025/118197/
https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-131a
https://www.tenable.com/cyber-exposure/a-look-inside-the-ransomware-ecosystem
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https://www.cisa.gov/news-events/cybersecurity-advisories/aa22-117a
https://www.tenable.com/cyber-exposure/2021-threat-landscape-retrospective
https://www.crowdstrike.com/blog/magniber-ransomware-caught-using-printnightmare-vulnerability/
https://therecord.media/printnightmare-vulnerability-weaponized-by-magniber-ransomware-gang
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https://www.tenable.com/blog/microsofts-august-2022-patch-tuesday-addresses-118-cves-cve-2022-34713
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https://github.com/VelesSecurity/CVE-2021-1675-PrintNightmare-Analysis
https://github.com/strangerHM/CVE-summarizer-and-lookup
https://github.com/nkoziel/cve-to-detection-rule
https://github.com/joertx07/printnightmare-detection-lab
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https://github.com/AlDawli/CVE-2021-34527-
https://github.com/saadabbasi-playground/detectionvalidation
https://github.com/Akalka/Ai-Windows-Penetration-testing-Assistant-
https://github.com/shaharyar0306/suricata-ips-autotuner
https://github.com/yashmoar11/RAG-poison
https://github.com/user70616E6461/phantom-intel
https://github.com/plusive27-max/cve-lookup
https://github.com/TamasCzaban/vuln-prioritization-scorer
https://github.com/iosec-shekhar/COIT
https://github.com/Willie-Conway/SOC-Simulator
https://github.com/iniyavan5/Nvd-cve-management
https://github.com/Gorstak-Zadar/Patcher
https://github.com/CVE-ORG/CVE-ORG
https://github.com/qrb661r/CVE-MITRE
https://github.com/ccordeiro/CVE-2021-1675
https://github.com/SarfiHabibova/CVE-Scraper
https://github.com/RaphaelKhoury/EPSS-Score-Extractor
https://github.com/VoiidByte/Impacket
https://github.com/ArtAtrium/PrintNightmare
https://github.com/spartancyberultron/WAF-Copilot
https://github.com/CyberUltron-Nikhil/WAF-Copilot
https://github.com/GlacierGossip/PrintNightmare
https://github.com/aldoClau98/CVE_CRAWLER
https://github.com/CameraShutterBug/PrintNightmare
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https://github.com/AndreLlorente/NVD_CVE_EXTRACTOR
https://github.com/ozzy76/cveCheck
https://github.com/Hirusha-N/CVE-2021-34527-CVE-2023-38831-and-CVE-2023-32784
https://github.com/0xSs0rZ/Windows_Exploit
https://github.com/Code-is-hope/CVE-Reporter
https://github.com/fardinbarashi/PsFix-CVE-2021-34527
https://github.com/Austin-Src/CVE-Checker
https://github.com/Zeyad-Azima/Remedy4me
https://github.com/r1skkam/PrintNightmare
https://github.com/hackerhouse-opensource/cve-2021-34527
https://github.com/SaintsConnor/Exploits
https://github.com/m8sec/CVE-2021-34527
https://github.com/SystemJargon/infosec_1
https://github.com/whoismept/IronSharp
https://github.com/thangnguyenchien/CVE
https://github.com/ly4k/PrintNightmare
https://github.com/Tomparte/PrintNightmare
https://github.com/0xirison/PrintNightmare-Patcher
https://github.com/galoget/PrintNightmare-CVE-2021-1675-CVE-2021-34527
https://github.com/syntaxbearror/PowerShell-PrintNightmare
https://github.com/Eutectico/Printnightmare
https://github.com/glorisonlai/printnightmare
https://github.com/WidespreadPandemic/CVE-2021-34527_ACL_mitigation
https://github.com/JumpsecLabs/PrintNightmare
https://github.com/pyonghe/PrintNightMareChecker
https://github.com/byt3bl33d3r/ItWasAllADream
https://github.com/rdboboia/disable-RegisterSpoolerRemoteRpcEndPoint
https://github.com/nemo-wq/PrintNightmare-CVE-2021-34527
https://github.com/glshnu/PrintNightmare
https://github.com/hlldz/CVE-2021-1675-LPE
https://github.com/evilashz/CVE-2021-1675-LPE-EXP
https://github.com/LaresLLC/CVE-2021-1675
https://github.com/cube0x0/CVE-2021-1675
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34527
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34527
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34527
http://packetstormsecurity.com/files/167261/Print-Spooler-Remote-DLL-Injection.html
Details
Published: 2021-07-02
Updated: 2026-08-10
Named Vulnerability: PrintNightmareKnown Exploited Vulnerability (KEV)
Risk Information
CVSS v2
Base Score: 9
Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C
Severity: High
CVSS v3
Base Score: 8.8
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
EPSS
EPSS: 0.99792