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OpenvpnApplication

CVE-2026-40215

HIGH · 7.4 CVSS v3.1 Published 2026-06-08
Fix available
A fix is available. Upgrade to 2.6.20 / 2.7.2 or later.
See remediation →
83/100
Remediation priority · High
Remotely reachable No privileges 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
A race condition in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote attackers to potentially cause a server crash or leak heap memory via a use-after-free triggered during TLS session promotion.

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

OpenVPN contains a race condition in versions 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 where during TLS session promotion, a use-after-free vulnerability can be triggered, potentially allowing remote attackers to cause server crashes (denial of service) or leak heap memory to the client.

MitigationUpgrade OpenVPN to a version beyond the affected range (later than 2.6.19 and 2.7.1) to receive the patch for this use-after-free vulnerability.

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
OpenvpnApplication
Affected:>= 2.6.0, < 2.6.20>= 2.7, < 2.7.2

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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. Determine the installed OpenVPN version
    Run 'openvpn --version' on the server and note the version number displayed
    Affected if The version is 2.6.0 through 2.6.19, or 2.7_alpha1 through 2.7.1 (or any 2.7.x version before 2.7.2)
  2. Locate the OpenVPN configuration file
    Common locations are /etc/openvpn/server.conf, /etc/openvpn/*.conf, or check the systemd service file for the --config directive
    Affected if The configuration file exists and is in active use by the OpenVPN server process
  3. Check if TLS session promotion is enabled
    Inspect the OpenVPN configuration file for the 'tls-verify' directive or any 'tls'-related directives that enable dynamic TLS session upgrading between client and server
    Affected if TLS session promotion or dynamic TLS upgrade features are configured and active
  4. Verify the OpenVPN service is running
    Check the running process with commands like 'ps aux | grep openvpn' or 'systemctl status openvpn'
    Affected if The OpenVPN server process is currently running with a vulnerable version and TLS session promotion is configured

You are affected if OpenVPN is running a version between 2.6.0-2.6.19 or 2.7_alpha1-2.7.1 AND TLS session promotion features are enabled in the configuration.

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 2.6.20 / 2.7.2 or later
Fixed in 2.6.202.7.2
Interim mitigation

Upgrade OpenVPN to a version beyond the affected range (later than 2.6.19 and 2.7.1) to receive the patch for this use-after-free vulnerability.

Recommended fix Moderate confidence

OpenVPN 2.6.20 or later, or OpenVPN 2.7.2 or later

  1. 1. Identify the current OpenVPN version installed by running 'openvpn --version' or checking the package manager.
  2. 2. If running OpenVPN 2.6.0 through 2.6.19, upgrade to version 2.6.20 or later.
  3. 3. If running OpenVPN 2.7_alpha1 through 2.7.1, upgrade to version 2.7.2 or later.
  4. 4. Download the appropriate installer or package from the official OpenVPN website (openvpn.net) or your distribution's package repository.
  5. 5. Install the updated version following standard upgrade procedures for your operating system.
  6. 6. Restart the OpenVPN service to apply the update.
  7. 7. Verify the new version is running with 'openvpn --version'.
Caveat Review OpenVPN release notes for version 2.6.20 and 2.7.2 for any configuration or feature changes that may affect your deployment

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

Fix this in Openvpn Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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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-2026-40215 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