# CVE-2026-62817 — Microsoft Windows Server 2019

> As of 2026-10-08, CVE-2026-62817 is a HIGH-severity vulnerability in Microsoft Windows Server 2019, CVSS v3.1 8.8, EPSS 0.5% (43.4th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-62817, most recently “Microsoft August 2026 Patch Tuesday: 400 Flaws Fixed, Including Lazarus-Exploited Zero-Day CVE-2026-68820 (AFD.sys) and Two Publicly Disclosed Zero-Days (CVE-2026-62832 "LegacyHive", CVE-2026-72971)”.

**Last updated:** 2026-10-08

## What is CVE-2026-62817?

Out-of-bounds write in Windows DNS allows an unauthorized attacker to execute code over an adjacent network.

The record classifies CVE-2026-62817 under weakness class [CWE-787](https://intel.threadlinqs.com/cwe/CWE-787). Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 5 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 60 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.8 — HIGH (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **EPSS (FIRST):** 0.5% probability of exploitation in the next 30 days, higher than 43.4% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-11, last modified 2026-10-08

## Is CVE-2026-62817 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Microsoft](https://intel.threadlinqs.com/vendors/microsoft): Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, Windows Server 2025, Windows Server 2025 (Server Core installation)

## How to fix CVE-2026-62817

No vendor patch reference has been recorded for CVE-2026-62817 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-62817

1 tracked threat in the Threadlinqs corpus references CVE-2026-62817, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Microsoft August 2026 Patch Tuesday: 400 Flaws Fixed, Including Lazarus-Exploited Zero-Day CVE-2026-68820 (AFD.sys) and Two Publicly Disclosed Zero-Days (CVE-2026-62832 "LegacyHive", CVE-2026-72971)](https://intel.threadlinqs.com/threat/TL-2026-1987) — CRITICAL · 2026-08-11

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [msrc.microsoft.com — vendor advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62817)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-62817
Full detection coverage and IOCs for threats exploiting CVE-2026-62817 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp