Description
Use after free in Windows Server allows an authorized attacker to elevate privileges locally.
Published: 2026-09-08
Score: 7.8 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability is a use‑after‑free condition that can be triggered by an authorized local user, potentially allowing them to execute code with elevated privileges, thereby enabling full system compromise. This weakness is classified as CWE‑416 and results in the loss of integrity and confidentiality for the compromised system.

Affected Systems

Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2), Windows 11 (versions 23H2, 24H2, 25H2, 26H1), and Windows Server (2016, 2019, 2022, 2025, including Server Core installations) are impacted by this flaw.

Risk and Exploitability

The CVSS score of 7.8 reflects a moderate to high severity. No EPSS value is available, making the likelihood of exploitation uncertain, and the vulnerability is not listed in the CISA KEV catalog. The attack vector is inferred to be local, requiring an authenticated user to trigger the use‑after‑free and achieve privilege escalation.

Generated by OpenCVE AI on September 8, 2026 at 18:57 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the Microsoft security update for CVE‑2026‑56177 as soon as possible.
  • Reboot affected systems to ensure the update takes effect.
  • Apply least‑privilege controls to local user accounts to reduce the opportunity for exploitation.

Generated by OpenCVE AI on September 8, 2026 at 18:57 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 08 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Description Use after free in Windows Server allows an authorized attacker to elevate privileges locally.
Title Windows Server Elevation of Privilege Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Weaknesses CWE-416
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*: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:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}

Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-09-08T18:34:29.967Z

Reserved: 2026-06-19T13:53:31.989Z

Link: CVE-2026-56177

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-08T18:17:42.563

Modified: 2026-09-08T18:39:13.460

Link: CVE-2026-56177

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-08T19:00:13Z

Weaknesses