dbcve.org
Azure Virtual Network GatewayApplication · Microsoft

CVE-2026-40411

HIGH · 8.8 CVSS v3.1 Published 2026-05-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Improper input validation in Azure Virtual Network Gateway allows an authorized attacker to execute code over a network.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Improper input validation in Azure Virtual Network Gateway enables an authenticated attacker to execute arbitrary code remotely over the network. The vulnerability stems from insufficient validation of input data processed by the gateway service, allowing injection or execution of attacker-controlled code.

MitigationMonitor Azure security advisories for the applicable patch and ensure Virtual Network Gateway instances are updated to the latest supported version. Review network access controls and principle of least privilege for gateway access.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Azure Virtual Network GatewayApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Azure Virtual Network Gateway is deployed
    Run 'az network vnet-gateway list --resource-group <rg-name>' or list all VNets in Azure Portal to see if any virtual network gateways exist in your subscriptions
    Affected if Any Azure Virtual Network Gateway resource exists in the subscription
  2. Verify administrative access to the gateway
    Run 'az role assignment list --assignee <user> --scope /subscriptions/<sub-id>/resourceGroups/<rg>/providers/Microsoft.Network/virtualNetworkGateways/<gw-name>' or review IAM assignments for the gateway resource
    Affected if Users or service principals outside the intended security group have Contributor or Owner roles on the gateway
  3. Check gateway public endpoint exposure
    Review the gateway's public IP configuration via 'az network public-ip list --resource-group <rg>' and check if the VPN gateway public IP is accessible from unnecessary networks, or review NSG rules applied to the gateway subnet
    Affected if The gateway has a public IP and NSGs or firewall rules allow inbound access from untrusted networks
  4. Review Azure Activity Log for gateway administrative actions
    Query Azure Activity Log filtered to Microsoft.Network/virtualNetworkGateways operations: 'az monitor activity-log list --resource-group <rg> --query "[?contains(operationName.value, 'virtualNetworkGateways')]"'
    Affected if There are unexpected or unauthorized configuration changes to the gateway
  5. Check for Point-to-Site or Site-to-Site VPN configurations
    Run 'az network vnet-gateway vpn-client show-url' or 'az network vnet-gateway list-advertised-routes' to see active VPN configurations
    Affected if Any VPN client or site-to-site connections are configured, as the vulnerability allows authenticated attackers to send crafted requests

A user is affected if they have any Azure Virtual Network Gateway deployed, since all versions are vulnerable to remote code execution via improper input validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Monitor Azure security advisories for the applicable patch and ensure Virtual Network Gateway instances are updated to the latest supported version. Review network access controls and principle of least privilege for gateway access.

Fix this in Azure Virtual Network Gateway Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40411 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data