CVE-2021-42278
CVE-2021-42278 is a high-severity vulnerability in Microsoft Windows Server 2004 with a CVSS 3.x base score of 7.5. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-04-11).
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v2: 6.5
- EPSS exploit prediction: 72% (99th percentile)
- Actively exploited: Yes — listed in CISA KEV (added 2022-04-11)
- EU (EUVD) id: EUVD-2021-29254
- EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-04-11)
- Affected product: Microsoft Windows Server 2004
- Published:
- Last modified:
Description
Active Directory Domain Services Elevation of Privilege Vulnerability
Frequently asked questions
- What is CVE-2021-42278?
- Active Directory Domain Services Elevation of Privilege Vulnerability
- How severe is CVE-2021-42278?
- CVE-2021-42278 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-42278 being actively exploited?
- Yes. CVE-2021-42278 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-04-11, which means active exploitation has been confirmed. It should be prioritised for remediation.
- What products are affected by CVE-2021-42278?
- CVE-2021-42278 primarily affects Microsoft Windows Server 2004. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-42278?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
- Does CVE-2021-42278 have an EU (EUVD) identifier?
- Yes. CVE-2021-42278 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-29254. It is also flagged as exploited in the EUVD (since 2022-04-11).
- When was CVE-2021-42278 published?
- CVE-2021-42278 was published on 2021-11-10 and last updated on 2026-08-19.
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42278
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42278
Affected products (9)
- cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:*
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