Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-78523

CVE-2026-78523HIGH

Microsoft Windows 10 Version 1607 — Windows DNS Server Denial of Service Vulnerability

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  N  N  H    7.5   .0098   61.0     —

AFFECTED
  Product                                            Versions        Fixed
  Windows 10 Version 1607                            10.0.14393.0 –  —
  Windows 10 Version 1809                            10.0.17763.0 –  —
  Windows Server 2012                                6.2.9200.0 –    —
  Windows Server 2012 (Server Core installation)     6.2.9200.0 –    —
  Windows Server 2012 R2                             6.3.9600.0 –    —
  Windows Server 2012 R2 (Server Core installation)  6.3.9600.0 –    —
  Windows Server 2016                                10.0.14393.0 –  —
  Windows Server 2016 (Server Core installation)     10.0.14393.0 –  —
  Windows Server 2019                                10.0.17763.0 –  —
  Windows Server 2019 (Server Core installation)     10.0.17763.0 –  —
  + 3 more

TIMELINE
  Aug 24  Reserved by microsoft
  Sep 8   Published (CNA: microsoft)
  Sep 10  RESCORED — CVE-2026-78523 (Microsoft Windows 10 Version 1607). CVSS 5.9 → 7.5 (NVD).

CWE-416 · CNA: microsoft · CVSS v3.1 · 1 reference · NVD status: Analyzed

Description

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 24, 2026	Reserved	Reserved by microsoft
September 8, 2026	Published	Published (CNA: microsoft)
September 10, 2026	RESCORED	RESCORED — CVE-2026-78523 (Microsoft Windows 10 Version 1607). CVSS 5.9 → 7.5 (NVD).

Affected

Affected products and packages — 13 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Microsoft	Windows 10 Version 1607	—	10.0.14393.0	—
Microsoft	Windows 10 Version 1809	—	10.0.17763.0	—
Microsoft	Windows Server 2012	—	6.2.9200.0	—
Microsoft	Windows Server 2012 (Server Core installation)	—	6.2.9200.0	—
Microsoft	Windows Server 2012 R2	—	6.3.9600.0	—
Microsoft	Windows Server 2012 R2 (Server Core installation)	—	6.3.9600.0	—
Microsoft	Windows Server 2016	—	10.0.14393.0	—
Microsoft	Windows Server 2016 (Server Core installation)	—	10.0.14393.0	—
Microsoft	Windows Server 2019	—	10.0.17763.0	—
Microsoft	Windows Server 2019 (Server Core installation)	—	10.0.17763.0	—
Microsoft	Windows Server 2022	—	10.0.20348.0	—
Microsoft	Windows Server 2025	—	10.0.26100.0	—
Microsoft	Windows Server 2025 (Server Core installation)	—	10.0.26100.0	—

Weaknesses

CWE-416

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78523 [vendor-advisory, patch]

Authoritative record: CVE-2026-78523 at cve.org

Vendors: microsoft

Weaknesses: CWE-416

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-78523 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.