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🎯 CVE-2021-34527 HIGH 8.8 🔥 EPSS 99.8% ⚠️ CISA KEV · 1772 T 🔓 Exploited 🇪🇺 EUVD
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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, Versi

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.

Klassifikation & Betroffenheit:
Microsoft Windows 10 Version 1809 10.0.17763.0 <10.0.17763.2029Windows 10 Version 1809 10.0.0 <10.0.17763.2029Windows 10 Version 1607 10.0.14393.0 <10.0.14393.4470Windows 10 Version 22H2 10.0.19045.0 <10.0.19045.2251Windows 10 Version 20H2 10.0.0 <10.0.19042.1083Windows 10 Version 1507 10.0.10240.0 <10.0.10240.18969Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.4470Windows Server 2019 10.0.17763.0 <10.0.17763.2029
Improper Control of Generation of Code ('Code Injection') 🎯 Medium

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

🛡️ Empfohlene Mitigation: Refactor your program so that you do not have to dynamically generate code.
Vollständige Definition bei MITRE ➔
⚔️ Typische Angriffsmuster (CAPEC):
CAPEC-35 · Leverage Executable Code in Non-Executab… (Very High) CAPEC-77 · Manipulating User-Controlled Variables (Very High) CAPEC-242 · Code Injection (High)
🎯 ATT&CK-Techniken (Kill-Chain-Verhalten):
T1027.006 · Obfuscated Files or Information: H… T1027.009 · Obfuscated Files or Information: E… T1564.009 · Hide Artifacts: Resource Forking
🧩 Ähnliche Schwachstellen (Hersteller/Klasse/Score-Band):
CVE-2026-69502 10.0 CVE-2026-69555 10.0 CVE-2026-65816 10.0 CVE-2026-65770 10.0 CVE-2026-65801 10.0
🧪 Exploit-Evidenz:
🐙 DenizSe/CVE-2021-34527 🐙 JohnHammond/CVE-2021-34527 🐙 twi1ight00/PrintNightmare 🐙 nemo-wq/PrintNightmare-CVE-2021- 🐙 rdboboia/disable-RegisterSpooler
📚 Referenzen & Quellen:
🇪🇺 Original-Eintrag (ENISA EUVD) 🇺🇸 NVD-Eintrag
Ausnutzungs-Zeitleiste:
CVSS-Vektor-Analyse: 8.8
AV · Angriffsvektor Netzwerk
AC · Komplexität Gering
PR · Privilegien Gering
UI · Interaktion Keine
S · Scope Unverändert
C · Vertraulichkeit Hoch
I · Integrität Hoch
A · Verfügbarkeit Hoch
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
Veröffentlicht:02.07.2021
Aktualisiert:10.08.2026 20:15
Assigner (CNA):microsoft
EUVD-ID:EUVD-2021-21181
Quellen: 🇪🇺 EUVD-Datenbank (ENISA) + 🇺🇸 NVD-Anreicherung · 24-h-Cache
CWE-94: Code Injection ✓ Offizieller Patch / Advisory verfügbar
💡 Gegenmaßnahme: Patch-Tuesday Update einspielen oder betroffene Dienste in Windows Defender isolieren.
🔴 Live Security Advisory & EPSS Exploit Radar

Zero-Day & Vulnerability Intelligence Hub

Echtzeit-Tracking mit EPSS Exploit-Wahrscheinlichkeiten, Angriffsvektor-Decodern und KI-Patch-Anleitungen.

🟢 SSE Realtime Synchronisiert ⚡ REST API (JSON) 📡 Digest (RSS) 📡 RSS Feed
90k+ 🇪🇺 EUVD-Datenbank
0 🔴 Critical im Radar
1 ⚠️ CISA KEV
1 🔓 Aktiv ausgenutzt
0 🧪 PoC verfügbar
8 🆕 Neu im KEV (7 T)
📊 Historien-Charts — Criticals-Trend · Vendors · EPSS-Verteilung
🔴 Criticals pro Monat (12 M) 2025-09: 190 2025-10: 316 2025-11: 257 2025-12: 426 2026-01: 431 2026-02: 418 2026-03: 652 2026-04: 574 2026-05: 683 2026-06: 942 2026-07: 1333 2026-08: 1329 7.551 Criticals gesamt
🏢 Top-Vendor-Veröffentlichungen (6 M) Adobe Apple Google Linux Microsoft Oracle Corporation
● Adobe ● Apple ● Google ● Linux ● Microsoft ● Oracle
📈 EPSS-Verteilung (Messungen)
Tier2026-08-292026-09-06
≥90 %40
≥50 %40
≥10 %30
<10 %304300
📈 EPSS-Riser (7 Tage) CVE-2016-4774 ↑ 0.8 % CVE-2016-4776 ↑ 0.8 % CVE-2016-4773 ↑ 0.8 %
Frühindikator · FIRST.org
Datenquellen & Methodik: Primärquelle ist die EUVD der ENISA (laufender Datenbank-Sync, alle 15 Minuten), abgeglichen mit dem CISA-KEV-Katalog und der NVD — Detail-Dossiers reichern fehlende Felder live per NVD an — mit Fallback auf CIRCL vulnerability-lookup (EU/Non-Profit, aggregiert CVE-, GitHub- und OSV-Advisories). Der CISA-KEV-Katalog (Known Exploited Vulnerabilities, ~1.700 aktiv ausgenutzte Schwachstellen) wird bei jedem Sync vollständig neu geladen und kreuzreferenziert — filterbar über die KEV-Pille. CVSS 3.1 wird nach Ampel-Logik aus Verteidigersicht dekodiert; EPSS bezeichnet die 30-Tage-Exploit-Wahrscheinlichkeit (FIRST.org).
🇪🇺 ENISA EUVD 🇺🇸 NVD ⚠️ CISA KEV ⚡ EPSS
Ökosystem & Hersteller Bedrohungs-Matrix:
Microsoft 1
Schweregrad & Status:
Hersteller (Datenbank-weit, 90.597 Einträge):
EPSS-Schwelle:
Quelle:
Schwachstellen-Kategorie (CWE):
🔍
8.8 HIGH
🇪🇺 EUVD ⚠️ KEV
EPSS 99.8%
CVE-2021-34527 🌐 Netzwerk (Remote) 🔑 Geringe Nutzerrechte nötig
🔓 Microsoft

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, Versi

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. A

CWE-94: Code Injection ✓ Offizieller Patch / Advisory verfügbar
💡 Gegenmaßnahme: Patch-Tuesday Update einspielen oder betroffene Dienste in Windows Defender isolieren.
02.07.2021
🛡️ Details ➔