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CVE-2026-45657

Microsoft Windows 11 23h2 use-after-free

9.8 CRITICALEPSS 0.97%
  1. Published9 Jun 2026

Description

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

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Windows 11 23h2< 10.0.22631.7219
Microsoft Windows 11 24h2< 10.0.26100.8655
Microsoft Windows 11 25h2< 10.0.26200.8655
Microsoft Windows 11 26h1< 10.0.28000.2269
Microsoft Windows Server 2022< 10.0.20348.5256
Microsoft Windows Server 2025< 10.0.26100.32995

Remediation

Fixed in
Microsoft Windows 11 23h2≥ 10.0.22631.7219
Microsoft Windows 11 24h2≥ 10.0.26100.8655
Microsoft Windows 11 25h2≥ 10.0.26200.8655
Microsoft Windows 11 26h1≥ 10.0.28000.2269
Microsoft Windows Server 2022≥ 10.0.20348.5256
Microsoft Windows Server 2025≥ 10.0.26100.32995

References

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Frequently asked

Is CVE-2026-45657 being actively exploited?

CVE-2026-45657 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.97%.

How severe is CVE-2026-45657?

CVE-2026-45657 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.97% probability of exploitation.

Which products are affected by CVE-2026-45657?

Affected products include Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows Server 2022, and 1 more.

How do I fix CVE-2026-45657?

Upgrade affected software to a fixed version, for example Microsoft Windows 11 23h2 10.0.22631.7219, Microsoft Windows 11 24h2 10.0.26100.8655, Microsoft Windows 11 25h2 10.0.26200.8655 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.