Unauthenticated remote code execution
Published Mar 11, 2021 · Updated Aug 19, 2026
Remote code execution in Microsoft Windows DNS Server allows remote attackers to execute code via crafted network requests. Microsoft has not published the vulnerable function, input structure, or erroneous operation in the DNS request-processing path. The DNS Server role must be installed and reachable; successful exploitation runs attacker-controlled code in the service security context.
Summary
What happened
Remote code execution in Microsoft Windows DNS Server allows remote attackers to execute code via crafted network requests. Microsoft has not published the vulnerable function, input structure, or erroneous operation in the DNS request-processing path. The DNS Server role must be installed and reachable; successful exploitation runs attacker-controlled code in the service security context.
The record
- CVE
- CVE-2021-26893
- Published
- Mar 11, 2021
- Updated
- Aug 19, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 11, 2021CVE publishedPublication date reported by the CVE source.
- Aug 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.1817
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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