CVE-2021-34527
Actively exploited. CVE-2021-34527 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2021-34527 is indexed in Metasploit and GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation.
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.
CSIRTS triage
- What
- The Print Spooler service improperly performs privileged file operations, allowing remote code execution.
- Who is affected
- Users of Microsoft Windows with the Print Spooler service.
- Urgency
- Remediation is critical due to active exploitation and high severity.
- Action
- Install the latest security updates for Windows Print Spooler.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 100% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2021-34527 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- MetasploitA Metasploit Framework module targets this CVE — weaponized, point-and-click exploitation.look it up ↗
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (1)
- criticalexploitedCVE-2021-34527: Microsoft Windows Print Spooler Remote Code Execution Vulnerabilitycisa-kev · 2021-11-03
External references
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[](https://www.csirts.com/cve/CVE-2021-34527)