Home/CVE/Heap-based buffer overflow in Windows Win32K - GRFX allows an authorized attacker to execute code locally.
CVE

CVE-2026-40403

Heap-based buffer overflow in Windows Win32K - GRFX allows an authorized attacker to execute code locally.

Heap-based buffer overflow in Windows Win32K - GRFX allows an authorized attacker to execute code locally.

HIGH · CVSS 8.8 EPSS 0.00017
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-122Heap-based Buffer Overflow
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Affected Products & Versions

14
microsoft windows 10 1607< 10.0.14393.9140
microsoft windows 10 1809< 10.0.17763.8755
microsoft windows 10 21h2< 10.0.19044.7291
microsoft windows 10 22h2< 10.0.19045.7291
microsoft windows 11 23h2< 10.0.22631.7079
microsoft windows 11 24h2< 10.0.26100.8390
microsoft windows 11 25h2< 10.0.26200.8390
microsoft windows 11 26h1< 10.0.28000.2113
▣

Scoring & Timeline

8.8
HIGH · CVSS v3.1 · secure@microsoft.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 May 2026 · 06:17 PM
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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Vendor Advisories

1
msrcCVE-2026-40403Remote Code Execution
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