EUVD-2026-56650
GHSA-mwmg-vvvw-m6x8
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local vector and low-privilege requirement confirmed by description ('authorized attacker', 'locally'); full C/I/A reflects kernel-level privilege escalation impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Integer underflow (wrap or wraparound) in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.
AnalysisAI
Privilege escalation via integer underflow in Windows HTTP.sys (the kernel-mode HTTP protocol stack) allows an authenticated local attacker to gain SYSTEM-level access on a broad range of Windows versions from Server 2012 through Server 2025 and Windows 10/11. The flaw is rooted in an integer wraparound condition (tagged by the reporter as a heap overflow mechanism) in the HTTP.sys kernel driver, enabling full compromise of confidentiality, integrity, and availability on the affected host. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an authenticated local session on the target Windows system - the CVSS PR:L metric confirms a low-privilege account (standard user or equivalent) is sufficient; no administrative rights are needed to trigger the vulnerability. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) accurately reflects a low-complexity local privilege escalation requiring only authenticated user-level access with no user interaction - a straightforward LPE primitive for post-exploitation. … 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 | The primary remediation is to apply Microsoft's monthly cumulative update to reach or exceed the fixed build version for each affected Windows release - exact target builds are listed in the affected products field above and in the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62741. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory your environment for all Windows Server 2012-2025 and Windows 10/11 systems using existing IT asset management tools. …
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External POC / Exploit Code
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