# CVE-2026-58598 — Microsoft Windows 10 Version 21H2

> As of 2026-10-08, CVE-2026-58598 is a HIGH-severity vulnerability in Microsoft Windows 10 Version 21H2, CVSS v3.1 7, EPSS 0.2% (9.2th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-58598, most recently “Microsoft July 2026 Patch Tuesday: 570 Vulnerabilities Fixed, Including 2 Actively Exploited Zero-Days (CVE-2026-56164, CVE-2026-56155)”.

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

## What is CVE-2026-58598?

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Backup Engine allows an authorized attacker to elevate privileges locally.

The record classifies CVE-2026-58598 under weakness classes [CWE-362](https://intel.threadlinqs.com/cwe/CWE-362), [CWE-416](https://intel.threadlinqs.com/cwe/CWE-416). Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, 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 104 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7 — HIGH (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 9.2% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-16, last modified 2026-10-08

## Is CVE-2026-58598 being exploited?

It currently carries a trending score of 16 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Microsoft](https://intel.threadlinqs.com/vendors/microsoft): Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1

## How to fix CVE-2026-58598

No vendor patch reference has been recorded for CVE-2026-58598 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-2026-58598

1 tracked threat in the Threadlinqs corpus references CVE-2026-58598, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Microsoft July 2026 Patch Tuesday: 570 Vulnerabilities Fixed, Including 2 Actively Exploited Zero-Days (CVE-2026-56164, CVE-2026-56155)](https://intel.threadlinqs.com/threat/TL-2026-1325) — CRITICAL · 2026-07-14

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. 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-2026-58598)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-58598
Full detection coverage and IOCs for threats exploiting CVE-2026-58598 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp