CVE-2021-34527
Confirmed PUBLISHEDWindows Print Spooler Remote Code Execution Vulnerability
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- Jul 02, 2021
- Exploitation Reported
- Nov 03, 2021
- CVSS
- 8.8 High
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Microsoft |
Windows 10 Version 1809
|
10.0.0 to < 10.0.17763.2029 |
Affected |
| Microsoft |
Windows Server 2019
|
10.0.0 to < 10.0.17763.2029 |
Affected |
| Microsoft |
Windows Server 2019 (Server Core installation)
|
10.0.0 to < 10.0.17763.2029 |
Affected |
| Microsoft |
Windows Server 2022
|
10.0.0 to < 10.0.20348.230 |
Affected |
| Microsoft |
Windows 10 Version 20H2
|
10.0.0 to < 10.0.19042.1083 |
Affected |
| Microsoft |
Windows Server version 20H2
|
10.0.0 to < 10.0.19042.1083 |
Affected |
| Microsoft |
Windows 11 version 21H2
|
10.0.0 to < 10.0.22000.318 |
Affected |
| Microsoft |
Windows 10 Version 21H2
|
10.0.0 to < 10.0.19044.1415 |
Affected |
| Microsoft |
Windows 11 version 22H2
|
10.0.0 to < 10.0.22621.674 |
Affected |
| Microsoft |
Windows 10 Version 22H2
|
10.0.0 to < 10.0.19045.2251 |
Affected |
| Microsoft |
Windows 10 Version 1507
|
10.0.0 to < 10.0.10240.18969 |
Affected |
| Microsoft |
Windows 10 Version 1607
|
10.0.0 to < 10.0.14393.4470 |
Affected |
| Microsoft |
Windows Server 2016
|
10.0.0 to < 10.0.14393.4470 |
Affected |
| Microsoft |
Windows Server 2016 (Server Core installation)
|
10.0.0 to < 10.0.14393.4470 |
Affected |
| Microsoft |
Windows 8.1
|
6.3.0 to < 6.3.9600.20046 |
Affected |
| Microsoft |
Windows Server 2008 Service Pack 2
|
6.0.0 to < 6.0.6003.21138 |
Affected |
| Microsoft |
Windows Server 2008 Service Pack 2 (Server Core installation)
|
6.0.0 to < 6.0.6003.21138 |
Affected |
| Microsoft |
Windows Server 2008 Service Pack 2
|
6.0.0 to < 6.0.6003.21138 |
Affected |
| Microsoft |
Windows Server 2008 R2 Service Pack 1
|
6.1.0 to < 6.1.7601.25633 |
Affected |
| Microsoft |
Windows Server 2008 R2 Service Pack 1 (Server Core installation)
|
6.0.0 to < 6.1.7601.25633 |
Affected |
| Microsoft |
Windows Server 2012
|
6.2.0 to < 6.2.9200.23383 |
Affected |
| Microsoft |
Windows Server 2012 (Server Core installation)
|
6.2.0 to < 6.2.9200.23383 |
Affected |
| Microsoft |
Windows Server 2012 R2
|
6.3.0 to < 6.3.9600.20046 |
Affected |
| Microsoft |
Windows Server 2012 R2 (Server Core installation)
|
6.3.0 to < 6.3.9600.20046 |
Affected |
CVE References
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34527 portal.msrc.microsoft.com · CVE Record https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CV...
- packetstormsecurity.com/files/167261/Print-Spooler-Remote-DLL-Inject... packetstormsecurity.com · CVE Record http://packetstormsecurity.com/files/167261/Print-Spooler-Remote-DLL-...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2021-11-03 00:00 UTC |
Scanner Artifacts
Nuclei and Metasploit references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Metasploit | https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/dcerpc/cve_2021_1675_printnightmare.rb | Apr 28, 2025 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
Exploitation Status
Exploited in the wild
Recorded 2021-11-03 00:00:00 UTC · CISA
Used in malware
Recorded 2021-11-03 00:00:00 UTC · CISA
Proof of concept available
Recorded 2021-07-01 12:12:16 UTC · GitHub
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Metasploit | https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/dcerpc/cve_2021_1675_printnightmare.rb | Apr 28, 2025 |
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2024-06-25 02:30:31 UTC · 0 stars
github · Created 2022-08-23 20:20:45 UTC · 109 stars
PrintNightmare (CVE-2021-34527) PoC Exploit
github · Created 2021-07-09 08:27:36 UTC · 3 stars
github · Created 2021-07-04 16:09:18 UTC · 6 stars
Cve-2021-1675 or cve-2021-34527? Detailed analysis and exploitation of windows print spooler 0day vulnerability！！！
github · Created 2021-07-03 15:15:12 UTC · 145 stars
PrintNightmare - Windows Print Spooler RCE/LPE Vulnerability (CVE-2021-34527, CVE-2021-1675) proof of concept exploits
github · Created 2021-07-02 12:10:49 UTC · 275 stars
github · Created 2021-07-01 12:12:16 UTC · 0 stars
Small Powershell Script to detect Running Printer Spoolers on Domain Controller
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
15:02 UTC about 1 year ago15:02 UTC · about 1 year ago
Metasploit module available
Exploit module available
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
First public exploitation report
Exploit observed in malware
-
21:25 UTC about 5 years ago21:25 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
12:12 UTC about 5 years ago12:12 UTC · about 5 years ago
Public PoC available
Public proof-of-concept code published
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-34527
{
"cve_id": "CVE-2021-34527",
"title": "Windows Print Spooler Remote Code Execution Vulnerability",
"affected_vendor": "Microsoft",
"affected_product": "Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, Windows 10 Version 20H2, Windows Server version 20H2, Windows 11 version 21H2, Windows 10 Version 21H2, Windows 11 version 22H2, Windows 10 Version 22H2, Windows 10 Version 1507, Windows 10 Version 1607, Windows Server 2016, Windows Server 2016 (Server Core installation), Windows 8.1, Windows Server 2008 Service Pack 2, Windows Server 2008 Service Pack 2 (Server Core installation), Windows Server 2008 Service Pack 2, Windows Server 2008 R2 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 8.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}