Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local attack vector with low privileges confirmed by description ('authorized attacker'); AC:L because no special conditions are described; full C/I/A from SYSTEM-level escalation with no scope change.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3DescriptionCVE.org
Heap-based buffer overflow in Windows SMB Client allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows SMB Client on Windows 11 version 26H1 enables a low-privileged authorized attacker to gain SYSTEM-level control via a heap-based buffer overflow (CWE-122). The CVSS 7.8 (High) score reflects low attack complexity and no user interaction required once local access is established, with full confidentiality, integrity, and availability impact on the compromised host. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an authorized local user account with at least low privilege (PR:L per CVSS) on a Windows 11 version 26H1 system at build 10.0.28000.0 through 10.0.28000.2703. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, score 7.8) characterizes this as a high-severity local privilege escalation: low attack complexity and no user interaction needed mean that once an attacker has local code execution, escalation to SYSTEM is technically straightforward. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply the Microsoft security update that advances Windows 11 version 26H1 to build 10.0.28000.2704 or later via Windows Update, Windows Server Update Services (WSUS), or the Microsoft Update Catalog; the authoritative advisory is at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62799. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all Windows 11 version 26H1 systems using Active Directory or endpoint detection tools to quantify patch scope. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-56660
GHSA-4ffr-gx27-qw7j