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CVE-2026-54990

Microsoft Windows 11 24h2 buffer overflow

9.8 CRITICALEPSS 0.82%
  1. Published14 Jul 2026

Description

Heap-based buffer overflow in Remote Desktop Client 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 24h2< 10.0.26100.8875
Microsoft Windows 11 25h2< 10.0.26200.8875
Microsoft Windows 11 26h1< 10.0.28000.2525 · < 10.0.28000.2269
Microsoft Windows Server 2025< 10.0.26100.33158

Remediation

Fixed in
Microsoft Windows 11 24h2≥ 10.0.26100.8875
Microsoft Windows 11 25h2≥ 10.0.26200.8875
Microsoft Windows 11 26h1≥ 10.0.28000.2525
Microsoft Windows Server 2025≥ 10.0.26100.33158

References

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Frequently asked

Is CVE-2026-54990 being actively exploited?

CVE-2026-54990 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.82%.

How severe is CVE-2026-54990?

CVE-2026-54990 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.82% probability of exploitation.

Which products are affected by CVE-2026-54990?

Affected products include Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows Server 2025.

How do I fix CVE-2026-54990?

Upgrade affected software to a fixed version, for example Microsoft Windows 11 24h2 10.0.26100.8875, Microsoft Windows 11 25h2 10.0.26200.8875, Microsoft Windows 11 26h1 10.0.28000.2525 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-54990 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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