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Linux Diagnostic ExtensionPlugin / extension · Microsoft

CVE-2026-23665

HIGH · 7.8 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 2.1.24 or later.
See remediation →
80/100
Remediation priority · High
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
Heap-based buffer overflow in Azure Linux Virtual Machines allows an authorized attacker to elevate privileges locally.

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

A heap-based buffer overflow vulnerability in Azure Linux Virtual Machines enables an authorized attacker to escalate privileges locally. The vulnerability resides in a system component of Azure Linux and can be exploited to gain higher-level access beyond the attacker's current authorized permissions.

MitigationApply available security patches for Azure Linux VMs and ensure proper access controls are maintained. Given this is a privilege escalation vulnerability, prioritize patching affected VM instances and monitor for any unusual local privilege activities.

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
Linux Diagnostic ExtensionPlugin / extension
Affected:>= 1.0.0, < 2.1.24

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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. Check if Microsoft Linux Diagnostic Extension is installed
    On the Azure VM, list installed extensions using 'az vm extension list -g <resource-group> --vm-name <vm-name>' or inspect /var/lib/waagent/ for Microsoft.Linux.Diagnostic extension files
    Affected if The extension is present on the system
  2. Retrieve the installed version of Microsoft Linux Diagnostic Extension
    Run 'waagent --version' or check the extension manifest in /var/lib/waagent/Microsoft.Linux.Diagnostic*/manifest.xml to find the version number
    Affected if A version number is returned that can be compared against the affected range
  3. Compare the installed version against the vulnerable range
    Verify if the installed version is >= 1.0.0 and < 2.1.24
    Affected if The installed version falls within >= 1.0.0 and < 2.1.24
  4. Confirm the extension is currently enabled or running
    Check extension status via 'az vm extension show -g <resource-group> --vm-name <vm-name> --name Microsoft.Linux.Diagnostic' or inspect if the diagnostic extension process is active on the VM
    Affected if The extension shows status as 'Enabled' or 'Running'

A user is affected if the Microsoft Linux Diagnostic Extension is installed with a version between 1.0.0 and 2.1.23 (inclusive) and the extension is enabled on the Azure Linux VM.

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.

dbcve · scoped
Upgrade available Upgrade to 2.1.24 or later
Fixed in 2.1.24
Interim mitigation

Apply available security patches for Azure Linux VMs and ensure proper access controls are maintained. Given this is a privilege escalation vulnerability, prioritize patching affected VM instances and monitor for any unusual local privilege activities.

Recommended fix High confidence

Linux Diagnostic Extension version 2.1.24 or later

  1. Identify affected Azure VMs running Linux Diagnostic Extension version < 2.1.24 using Azure CLI: az vm extension list --resource-group <rg-name> --vm-name <vm-name>
  2. Update the Linux Diagnostic Extension to version 2.1.24 or later using Azure CLI: az vm extension set --resource-group <rg-name> --vm-name <vm-name> --name LinuxDiagnostic --publisher Microsoft.Azure.Diagnostics --version 2.1.24
  3. Alternatively, update via Azure PowerShell: Set-AzVMExtension -ResourceGroupName <rg-name> -VMName <vm-name> -Name LinuxDiagnostic -Publisher Microsoft.Azure.Diagnostics -ExtensionVersion 2.1.24
  4. Verify the extension updated successfully by checking the extension status: az vm extension show --resource-group <rg-name> --vm-name <vm-name> --name LinuxDiagnostic
  5. Ensure the reported version is 2.1.24 or higher to confirm remediation

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Diagnostic Extension Scoped from the published advisory
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,730
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,368.

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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-2026-23665 in production — separate from our analysis above.

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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