Windows
CVE-2026-21245
HIGH
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.
AnalysisAI
Windows Kernel heap overflow in Windows 11 25h2 and Windows Server 2025 enables authenticated local attackers to achieve privilege escalation with high impact on confidentiality, integrity, and availability. The vulnerability requires local access and user privileges but no user interaction, making it a practical attack vector for lateral movement within systems. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Attacker must have local login access to Windows system. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.8 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to compromise the affected system. |
| Remediation | Monitor vendor advisories for a patch. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all Windows systems and identify those with high-value assets or sensitive data access; disable unnecessary local admin accounts and review privileged access policies. …
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External POC / Exploit Code
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