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CRITICAL severity

CVE-2026-45602 — Windows 10 21h2

CRITICAL

CVE-2026-45602 is a critical-severity (CVSS 9.1) CWE-349 vulnerability in microsoft windows 10 21h2. A fix is available — see the affected versions and patch details below.

No cwe for this issue in Windows DHCP Server allows an unauthorized attacker to perform tampering over a network.

Published
Updated
Affected
13 products
Patched
See advisory
Exploits
None indexed
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45602.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs32th percentile — riskier than 32% of all scored CVEsHighest risk
0.00%0.30%0.60%0.90%0.4%0.4%0.4%0.4%0.4%Jul 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-45602 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

No cwe for this issue in Windows DHCP Server allows an unauthorized attacker to perform tampering over a network.

Affected Products

13 products · 20 configurations
OS
windows 10 21h2microsoft
< 10.0.19044.7417
range
OS
windows 10 22h2microsoft
< 10.0.19045.7417
range
OS
windows 10 1607microsoft
< 10.0.14393.9234
range
OS
windows 10 1809microsoft
< 10.0.17763.8880
range
OS
windows 11 23h2microsoft
< 10.0.22631.7219
range
OS
windows 11 24h2microsoft
< 10.0.26100.8655
range

Detection & mitigation playbook

Vendor / appliance
  1. Detect

    Inventory every microsoft windows 10 21h2 deployment and check each version against the affected-products list above.

  2. Fix

    Apply the microsoft windows 10 21h2 security patch or hotfix for CVE-2026-45602 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

No cwe for this issue in Windows DHCP Server allows an unauthorized attacker to perform tampering over a network.
O3 Security · Runtime Protection

Is CVE-2026-45602 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

CVE-2026-45602: Windows 10 21h2 (Critical 9.1)