CVE-2026-40411Network attack vector

Authenticated remote code execution

Published May 22, 2026 · Updated May 22, 2026

Improper input validation in Microsoft Azure Virtual Network Gateway allows remote authenticated users to execute code over a network. Microsoft has not disclosed the affected request, field, parser, or validation failure within the gateway service. Low-privileged authenticated access is required; successful exploitation executes code in the service context without user interaction.

CVSS severity9.9
Critical
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Microsoft Azure Virtual Network Gateway allows remote authenticated users to execute code over a network. Microsoft has not disclosed the affected request, field, parser, or validation failure within the gateway service. Low-privileged authenticated access is required; successful exploitation executes code in the service context without user interaction.

The record

CVE
CVE-2026-40411
Published
May 22, 2026
Updated
May 22, 2026
Vendor
Microsoft
Product
Azure Virtual Network Gateway
Classifications
CWE-20, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=-

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Azure Virtual Network Gatewayversion=-

Published CVSS scores

8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.9Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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