CVE-2021-26877
Windows DNS Server Remote Code Execution Vulnerability
Windows DNS Server Remote Code Execution Vulnerability
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Windows DNS Server Remote Code Execution Vulnerability
Windows DNS Server Remote Code Execution Vulnerability
- Record
CVE-2021-26877- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
EUVDEUVD-2021-13661
Windows DNS Server Remote Code Execution Vulnerability
- Record
EUVD-2021-13661- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-86v8-8qp7-vj9r
Windows DNS Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26893,...
Windows DNS Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26893, CVE-2021-26894, CVE-2021-26895, CVE-2021-26897.
- Record
GHSA-86v8-8qp7-vj9r- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
NVD
Windows DNS Server Remote Code Execution Vulnerability
- Record
CVE-2021-26877- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Updated
- 2026-11-02
Affected products
- microsoft windows server 2008 r2 service pack 1
- microsoft windows server 2008 r2 service pack 1 (server core installation)
- microsoft windows server 2008 service pack 2
- microsoft windows server 2008 service pack 2 (server core installation)
- microsoft windows server 2012
- microsoft windows server 2012 (server core installation)
- microsoft windows server 2012 r2
- microsoft windows server 2012 r2 (server core installation)
- microsoft windows server 2016
- microsoft windows server 2016 (server core installation)
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26877 is a critical vulnerability (CVSS 9.8) in Microsoft Windows Server 2008 R2 Service Pack 1, published March 11, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 17.3%, the 97th percentile. No source names a fixed version.