CriticalCVE-2022-21999

    Windows Print Spooler Elevation of Privilege Vulnerability (CVE-2022-21999)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    Windows Print Spooler Elevation of Privilege Vulnerability

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update Microsoft Windows 10 Version 1809 to version 10.0.17763.2565, Microsoft Windows Server 2019 to version 10.0.17763.2565, Microsoft Windows Server 2019 (Server Core installation) to version 10.0.17763.2565. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.2565
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.2565
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.2565
    • Microsoft Windows 10 Version 1909 lt 10.0.0..10.0.18363.2094
    • Microsoft Windows 10 Version 21H1 lt 10.0.0..10.0.19043.1526
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.524
    • Microsoft Windows 10 Version 20H2 lt 10.0.0..10.0.19042.1526
    • Microsoft Windows Server version 20H2 lt 10.0.0..10.0.19042.1526
    • Microsoft Windows 11 version 21H2 lt 10.0.0..10.0.22000.493
    • Microsoft Windows 10 Version 21H2 lt 10.0.19043.0..10.0.19044.1526
    • Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.19204
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.4946
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.4946
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.4946
    • Microsoft Windows 7 lt 6.1.0..6.1.7601.25860
    • Microsoft Windows 7 Service Pack 1 lt 6.1.0..6.1.7601.25860
    • Microsoft Windows 8.1 lt 6.3.0..6.3.9600.20269
    • Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.21374
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.21374
    • Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.25860
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.25860
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.23605
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.23605
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.20269
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.20269
    Fixed in
    • Microsoft Windows 10 Version 1809 10.0.17763.2565
    • Microsoft Windows Server 2019 10.0.17763.2565
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.2565
    • Microsoft Windows 10 Version 1909 10.0.18363.2094
    • Microsoft Windows 10 Version 21H1 10.0.19043.1526
    • Microsoft Windows Server 2022 10.0.20348.524
    • Microsoft Windows 10 Version 20H2 10.0.19042.1526
    • Microsoft Windows Server version 20H2 10.0.19042.1526
    • Microsoft Windows 11 version 21H2 10.0.22000.493
    • Microsoft Windows 10 Version 21H2 10.0.19044.1526
    • Microsoft Windows 10 Version 1507 10.0.10240.19204
    • Microsoft Windows 10 Version 1607 10.0.14393.4946
    • Microsoft Windows Server 2016 10.0.14393.4946
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.4946
    • Microsoft Windows 7 6.1.7601.25860
    • Microsoft Windows 7 Service Pack 1 6.1.7601.25860
    • Microsoft Windows 8.1 6.3.9600.20269
    • Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21374
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.21374
    • Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.25860
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.25860
    • Microsoft Windows Server 2012 6.2.9200.23605
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.23605
    • Microsoft Windows Server 2012 R2 6.3.9600.20269
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.20269

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    41.0 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.7

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    242.28 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploited
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    41.0 %
    Elevated — model estimates 10-50% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    98.7
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This is a reliable, low-complexity local privilege escalation to SYSTEM that needs no user interaction. Public exploit code has made it a staple of post-exploitation toolkits. CISA flags confirmed use in ransomware campaigns, typically in the chain initial access (phishing, VPN, RDP) → spooler escalation → credential dumping → domain takeover. Exploitation likelihood is very high and the spooler runs by default on almost every Windows host. Treat this as high-to-critical despite the local vector, particularly on multi-user systems and Tier-0 assets. Any host still unpatched against a 2022 fix should also be raised as a significant finding in your NIS2 vulnerability-management reporting.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the February 2022 security update (Patch Tuesday, 8 Feb 2022) or any later cumulative update. Per the context, builds below these levels are affected: Windows 10 1507 10.0.10240.19204, 1607 10.0.14393.4946, 1809 10.0.17763.2565, 1909 10.0.18363.2094, 20H2/21H1/21H2 10.0.19042/19043/19044.1526, Windows 11 21H2 10.0.22000.493. Look up the specific KB numbers and Windows Server coverage in the MSRC advisory for CVE-2022-21999.
      • Reconcile your inventory: Pull build numbers via Intune, SCCM/MECM or Get-ComputerInfo. Flag everything below the listed builds and start with multi-user hosts: RDS/terminal servers, VDI and jump hosts.
      • Disable the Print Spooler wherever printing isn't required, especially on domain controllers, Tier-0 servers and admin workstations: Stop-Service Spooler -Force; Set-Service Spooler -StartupType Disabled. Enforce this via GPO or Intune.
      • Run a compromise check:
        • Enumerate SpoolDirectory values under HKLM\SYSTEM\CurrentControlSet\Control\Print\Printers\* that don't point to C:\Windows\System32\spool\PRINTERS.
        • Hunt for DLLs under C:\Windows\System32\spool\drivers\x64\ that aren't signed by Microsoft or a known printer vendor.
      • On any hit: Isolate the host via EDR and rotate credentials for every account that has logged on to it. SYSTEM access means LSASS secrets should be treated as exposed. Then review lateral movement by those accounts.

    2. Runbook step 2

      Mitigation layers

      • Configuration: On print servers that must stay up, apply the "Point and Print Restrictions" GPO and enforce RestrictDriverInstallationToAdministrators=1 under HKLM\Software\Policies\Microsoft\Windows NT\Printers\PointAndPrint. This doesn't fully neutralise this local bug, but it shuts down related spooler attack chains.
      • Endpoint hardening: Use WDAC or AppLocker DLL rules so spoolsv.exe can only load signed driver DLLs. Set the EDR policy for unsigned image loads into spoolsv.exe to block.
      • IAM / least privilege: Tighten registry ACLs on HKLM\...\Control\Print\Printers and printer management permissions so standard users can't modify printer properties such as SpoolDirectory. Minimise local admin rights with LAPS and tiering.
      • Attack surface: Restrict "Allow log on locally" and RDP logon on servers to administrative groups. Exploitation requires a low-privileged local foothold, typically from phishing, a stolen VPN account or exposed RDP.
      • Network segmentation: Place central print servers in a dedicated VLAN. Only allow SMB (445/tcp) and RPC (135/tcp plus the dynamic range) from clients to those designated servers. This limits lateral movement after a successful escalation.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 13 (registry value set): TargetObject containing \Control\Print\Printers\ with SpoolDirectory, where Details doesn't point to spool\PRINTERS. KQL: DeviceRegistryEvents | where RegistryKey has @"\Control\Print\Printers\" and RegistryValueName == "SpoolDirectory" and RegistryValueData !has @"spool\PRINTERS"
      • Sysmon EID 11 + EID 7: A *.dll is written to \spool\drivers\x64\4\ or to a newly created directory under \spool\drivers\ by any process other than spoolsv.exe or TrustedInstaller. This is followed by spoolsv.exe loading that DLL with Signed=false.
      • Process ancestry (Sysmon EID 1 / Security 4688): ParentImage|endswith: '\spoolsv.exe' spawning cmd.exe, powershell.exe, rundll32.exe or whoami.exe. This is a high-fidelity Sigma candidate.
      • Print service logs:
        • Microsoft-Windows-PrintService/Admin EID 808 (plug-in load failure).
        • Microsoft-Windows-PrintService/Operational EID 316 (driver added) outside change windows.
        • Unexpected spooler restarts (System EID 7036/7031).
      • Junction creation: Standard users creating reparse points that target C:\Windows\System32\spool\drivers. Detect via EDR telemetry, or via mklink /J in 4688 command lines with command-line auditing enabled.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Windows Print Spooler Elevation of Privilege Vulnerability

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    MicrosoftWindows 10 Version 1507
    • 10.0.10240.0 – < 10.0.10240.19204
    • 10.0.10240.19204
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.4946
    • 10.0.14393.4946
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.2565
    • 10.0.17763.2565
    MicrosoftWindows 10 Version 1909
    • 10.0.0 – < 10.0.18363.2094
    • 10.0.18363.2094
    MicrosoftWindows 10 Version 20H2
    • 10.0.0 – < 10.0.19042.1526
    • 10.0.19042.1526
    MicrosoftWindows 10 Version 21H1
    • 10.0.0 – < 10.0.19043.1526
    • 10.0.19043.1526
    MicrosoftWindows 10 Version 21H2
    • 10.0.19043.0 – < 10.0.19044.1526
    • 10.0.19044.1526
    MicrosoftWindows 11 version 21H2
    • 10.0.0 – < 10.0.22000.493
    • 10.0.22000.493
    MicrosoftWindows 7
    • 6.1.0 – < 6.1.7601.25860
    • 6.1.7601.25860
    MicrosoftWindows 7 Service Pack 1
    • 6.1.0 – < 6.1.7601.25860
    • 6.1.7601.25860
    MicrosoftWindows 8.1
    • 6.3.0 – < 6.3.9600.20269
    • 6.3.9600.20269
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • 6.1.7601.0 – < 6.1.7601.25860
    • 6.1.7601.25860
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • 6.1.7601.0 – < 6.1.7601.25860
    • 6.1.7601.25860
    MicrosoftWindows Server 2008 Service Pack 2
    • 6.0.6003.0 – < 6.0.6003.21374
    • 6.0.6003.21374
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • 6.0.6003.0 – < 6.0.6003.21374
    • 6.0.6003.21374
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.23605
    • 6.2.9200.23605
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.23605
    • 6.2.9200.23605
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.20269
    • 6.3.9600.20269
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.20269
    • 6.3.9600.20269
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.4946
    • 10.0.14393.4946
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.4946
    • 10.0.14393.4946
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.2565
    • 10.0.17763.2565
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.2565
    • 10.0.17763.2565
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.524
    • 10.0.20348.524
    MicrosoftWindows Server version 20H2
    • 10.0.0 – < 10.0.19042.1526
    • 10.0.19042.1526

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_1909—
    Windowsmicrosoftwindows_10_20h2—
    Windowsmicrosoftwindows_10_21h1—
    Windowsmicrosoftwindows_10_21h2—
    Windowsmicrosoftwindows_11_21h2—
    Windowsmicrosoftwindows_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—
    Windowsmicrosoftwindows_server_2022—
    Windowsmicrosoftwindows_server_20h2—

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • Microsoft Security Update GuideWindows Print Spooler Elevation of Privilege VulnerabilityVendor advisory, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-21999government-resource, US government resource
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    Badge preview for CVE-2022-21999
    <a href="https://intel.neosec.eu/en/cve/CVE-2022-21999"><img src="https://intel.neosec.eu/badge/cve/CVE-2022-21999.svg?lang=en" alt="CVE-2022-21999 – NEOSEC Intel" height="20"></a>