CVE-2026-77505

Windows DNS Server Remote Code Execution Vulnerability

Published Sep 8, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
Description
Use after free in DNS Server allows an unauthorized attacker to execute code over a network.

Analysis

AI-generated

Technical impact

A use‑after‑free flaw in Microsoft Windows DNS Server allows an unauthorized attacker to cause code execution on the system. The vulnerability is formally identified as CWE‑416 and carries a CVSS score of 8.1, indicating a high‑severity risk. When exploited, the attacker can run arbitrary code with the privileges of the DNS Server service, potentially compromising the entire host and any services it supports.

Affected Systems

The flaw affects Microsoft Windows 10 Version 1607 and Version 1809, as well as Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025 (including Server Core installations). Only the versions listed in the CNA data are known to be vulnerable; no other builds are reported.

Risk and Exploitability

The CVSS score of 8.1 denotes a high severity, and the EPSS score is < 1 %, indicating a low but non‑zero likelihood of exploitation. The flaw is not listed in CISA’s KEV catalog. Attackers can target the vulnerability remotely over the network by sending malicious DNS traffic to a vulnerable DNS Server, exploiting the use‑after‑free condition to gain code execution. No special user privileges or configuration are required beyond network reachability.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Install the latest Microsoft security update for CVE-2026-77505 from the Microsoft Security Update Guide.
  • If the DNS role is not required, remove or disable the DNS Server service; alternatively, block inbound DNS traffic from untrusted networks using firewall rules.
  • Apply least‑privilege principles by ensuring that the DNS Server service runs with the minimal privileges necessary, and monitor DNS logs for anomalous activity.

Generated by OpenCVE AI on September 9, 2026 at 23:47 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*: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:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*
Type Values Removed Values Added
First Time appeared Microsoft windows Server 2012 (server Core Installation)
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 2025 (server Core Installation)
Vendors & Products Microsoft windows Server 2012 (server Core Installation)
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 2025 (server Core Installation)
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description Use after free in DNS Server allows an unauthorized attacker to execute code over a network.
Title Windows DNS Server Remote Code Execution Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
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_server_2012:*:*:*:*:*:*:x64:*
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:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}