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Critical· 9.8

CVE-2026-47291

This vulnerability is an integer overflow in Windows HTTP.sys that lets an attacker run code on a target machine over the network. It affects many recent Windows 10 and Windows 11 releases. The flaw can be triggered without authentication or user interaction.

publishedJun 9, 2026
last modifiedJul 23, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
23%
97th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Sep 6, 2026

No official fix yet. If none appears within 45 days of first tracking, this entry is removed automatically.

01

Who is affected

Microsoft Windows 10 (1607, 1809, 21H2, 22H2) and Windows 11 (23H2, 24H2, 25H2) versions are affected.

02

Real-world impact

An attacker could run arbitrary code on the affected system, potentially taking full control, stealing data, or installing malware.

03

Why this severity

The CVSS score of 9.8 reflects that the flaw is exploitable from the network, requires no privileges, and can compromise confidentiality, integrity, and availability. The high impact and low effort make it critical.

04

What to do about it

no official fix yet

No official fix or mitigation is documented in the sources yet. Monitor the vendor advisory and apply the patch as soon as it is released.

No fix documented in sources

05

Timeline

  1. Jun 9, 2026 · Jun 9, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 23, 2026 · 12d ago
    Advisory updated
    The NVD record was last revised.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
CVE-2026-47291: This vulnerability is an integer overflow in Windows HTTP.sys that let · Vulnary