Description
Improper input validation in Windows Active Directory allows an authorized attacker to execute code over an adjacent network.
Published: 2026-04-14
Score: 8 High
EPSS: < 1% Very Low
KEV: No
Impact: Remote Code Execution
Action: Immediate Patch
AI Analysis

Impact

Improper input validation in Windows Active Directory enables an attacker with authorized access to execute arbitrary code on domain controllers and potentially other machines in the same network. The flaw can compromise confidentiality, integrity, and availability of the affected systems. Based on the description, it is inferred that exploitation may allow lateral movement to other domain‑joined machines that share the same network segment.

Affected Systems

The vulnerability affects Microsoft Windows Server products ranging from 2012 R2 through 2025, including the 23H2 edition, with both full and Server Core installations impacted. These include Windows Server 2012 R2, 2016, 2019, 2022, 2025, and the 23H2 edition, each edition of these operating systems is affected.

Risk and Exploitability

The CVSS score of 8 indicates high severity. No EPSS score is available, and the issue is not listed in the CISA KEV catalog. Exploitation requires the attacker to be authenticated against Active Directory; therefore the likely attack vector is a network‑based method such as an LDAP or RPC interaction from a trusted or compromised domain account. Given the high severity and remote nature of the flaw, organizations with vulnerable domain controllers face substantial risk if adversaries gain the necessary credentials.

Generated by OpenCVE AI on April 14, 2026 at 20:39 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the Microsoft security update released for CVE‑2026‑33826 to all affected Windows Server systems.
  • Ensure that both full and Server Core installations of Windows Server 2012 R2 through 2025, including the 23H2 edition, are updated.
  • If patching cannot be performed immediately, restrict domain controller access from untrusted network segments or environments.
  • Monitor event logs for unusual Active Directory activity or failed authentication attempts.

Generated by OpenCVE AI on April 14, 2026 at 20:39 UTC.

Tracking

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Advisories

No advisories yet.

History

Wed, 15 Apr 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2022, 23h2 Edition (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Vendors & Products Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2022, 23h2 Edition (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)

Tue, 14 Apr 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 14 Apr 2026 17:30:00 +0000

Type Values Removed Values Added
Description Improper input validation in Windows Active Directory allows an authorized attacker to execute code over an adjacent network.
Title Windows Active Directory Remote Code Execution Vulnerability
First Time appeared Microsoft
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
Weaknesses CWE-20
CPEs cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
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_2025:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_23h2:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}


Subscriptions

Microsoft Windows Server 2012 R2 Windows Server 2012 R2 Windows Server 2012 R2 (server Core Installation) Windows Server 2016 Windows Server 2016 (server Core Installation) Windows Server 2019 Windows Server 2019 (server Core Installation) Windows Server 2022 Windows Server 2022, 23h2 Edition (server Core Installation) Windows Server 2025 Windows Server 2025 (server Core Installation) Windows Server 23h2
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-04-15T21:54:46.834Z

Reserved: 2026-03-24T00:52:01.352Z

Link: CVE-2026-33826

cve-icon Vulnrichment

Updated: 2026-04-14T19:11:49.897Z

cve-icon NVD

Status : Received

Published: 2026-04-14T18:17:35.267

Modified: 2026-04-14T18:17:35.267

Link: CVE-2026-33826

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-15T15:00:06Z

Weaknesses