CISA-confirmed known exploited vulnerability

CVE-2021-34527

Microsoft Windows Print Spooler Remote Code Execution Vulnerability

Microsoft · Windows

Vulnerability details

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.

Added to CISA KEV: 2021-11-03

Ransomware campaign use: Known

CISA due date: 2022-05-03

Defensive guidance from CISA

Apply updates per vendor instructions.

This is the source's required-action field, not an independently validated patch procedure. Refer to the vendor for exact affected versions and fixes.

Source catalog date: 2026-11-06T19:44:45.1797Z · Last retrieved: 2026-11-06 21:02:26 UTC

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