November 3, 2021 · Applied Cybernetics Group
CVE-2021-34527 — Microsoft Windows
known ransomware use
Microsoft Windows Print Spooler Remote Code Execution Vulnerability
- Added to KEV
2021-11-03- Federal due date
2022-05-03- Vendor
- Microsoft
- Product
- Windows
- EPSS
- 99.9th percentile (score 0.942, as of
2026-06-08) - NVD CVSS v3.1
- —
- Ransomware use
- Known
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2021-34527
CISA short description
Microsoft Windows Print Spooler contains an unspecified vulnerability due to the Windows Print Spooler service improperly performing privileged file operations. Successful exploitation allows an attacker to perform remote code execution with SYSTEM privileges. The vulnerability is also known under the moniker of PrintNightmare.
Required action
Apply updates per vendor instructions.