CVE-2026-45657: Windows Kernel Remote Code Execution Vulnerability

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 28 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

15.5%

EPSS score, percentile 96.8 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• from 10.0.22631.0 to before 10.0.22631.7219
• from 10.0.22631.0 to before 10.0.22631.7219
• from 10.0.26100.0 to before 10.0.26100.8655
• from 10.0.26200.0 to before 10.0.26200.8655
• from 10.0.28000.0 to before 10.0.28000.2269
• from 10.0.20348.0 to before 10.0.20348.5256

and 2 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Advisories and patches

• Windows Kernel Remote Code Execution Vulnerability (Vendor advisory, Patch)

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Use after free in Windows Kernel allows an unauthorized attacker to execute code over a network.

Summary: CVE record, as of 28 Oct 2026.

• CISA has not added CVE-2026-45657 to its Known Exploited Vulnerabilities (KEV) catalog, as of 28 Oct 2026.
• The CVE record was published on 9 Jun 2026.
• The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 15.5% (percentile 96.8), as of 28 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Windows Kernel Remote Code Execution Vulnerability

Use after free in Windows Kernel allows an unauthorized attacker to execute code over a network.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-416: Use After Free
• CWE-122: Heap-based Buffer Overflow

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

Known exploited Microsoft vulnerabilities

• CVE-2026-96951: Microsoft Windows Command Injection Vulnerability (added 13 Oct 2026)
• CVE-2026-65660: Microsoft SharePoint Code Injection Vulnerability (added 25 Sep 2026)
• CVE-2026-81963: Microsoft Windows Link Following Vulnerability (added 8 Sep 2026)
• CVE-2026-85880: Microsoft Windows Heap-Based Buffer Overflow Vulnerability (added 8 Sep 2026)
• CVE-2019-1068: Microsoft SQL Server Remote Code Execution Vulnerability (added 26 Aug 2026)