CVE-2021-34527: Microsoft Windows Print Spooler Remote Code Execution Vulnerability
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
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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Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-34527
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2021-34527Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 100% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2021-34527 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Microsoft Windows Print
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- criticalexploitedCVE-2022-38028: Microsoft Windows Print Spooler Privilege Escalation Vulnerabilitycisa-kev · 2024-04-23
- criticalexploitedCVE-2022-41073: Microsoft Windows Print Spooler Privilege Escalation Vulnerabilitycisa-kev · 2022-11-08
- criticalexploitedCVE-2022-22718: Microsoft Windows Print Spooler Privilege Escalation Vulnerabilitycisa-kev · 2022-04-19
- criticalexploitedCVE-2022-21999: Microsoft Windows Print Spooler Privilege Escalation Vulnerabilitycisa-kev · 2022-03-25
- criticalexploitedCVE-2021-1675: Microsoft Windows Print Spooler Remote Code Execution Vulnerabilitycisa-kev · 2021-11-03
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