dbcve.org
OpenvpnApplication

CVE-2025-13086

HIGH · 7.5 CVSS v3.1 Published 2025-12-03
Fix available
A fix is available. Upgrade to 2.6.16 or later.
See remediation →
84/100
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
Improper validation of source IP addresses in OpenVPN version 2.6.0 through 2.6.15 and 2.7_alpha1 through 2.7_rc1 allows an attacker to open a session from a different IP address which did not initiate the connection resulting in a denial of service for the originating client

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 · high confidence

OpenVPN fails to properly validate source IP addresses in versions 2.6.0-2.6.15 and 2.7_alpha1-2.7_rc1, allowing an attacker to hijack a session from a different IP than the one that initiated the connection, causing denial of service for the legitimate client.

MitigationUpgrade to OpenVPN 2.6.16 or later, or 2.7_rc2 or later, to remediate the improper source IP validation 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, < 2.6.16= 2.7

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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. Check installed OpenVPN version
    Run 'openvpn --version' or 'openvpn --help' to see the version number, or check via package manager (dpkg -l openvpn, rpm -q openvpn)
    Affected if Version is 2.6.0 through 2.6.15, or 2.7_alpha1 through 2.7_rc1
  2. Confirm OpenVPN is configured as a server accepting client connections
    Inspect the server configuration file (typically /etc/openvpn/server.conf or /etc/openvpn/*.conf) and look for 'mode server' or 'tls-server' directive, or check running processes for 'openvpn --server' or similar
    Affected if OpenVPN is running as a server accepting incoming client connections
  3. Check for x509 username field configuration
    Search config files for 'x509-username-field' directive using 'grep -r x509-username-field /etc/openvpn/'
    Affected if The x509-username-field option is configured, as this feature relies on source IP validation that is flawed in affected versions
  4. Check for IP-based access control configurations
    Look for 'ifconfig-push' directives in CCD files or 'iroute' configurations in /etc/openvpn/ccd/, and check for any 'remote' statements that specify IP restrictions
    Affected if IP-based routing or access control is configured, as the vulnerability allows bypassing these controls by hijacking sessions from different IPs

You are affected if OpenVPN version is 2.6.0-2.6.15 or 2.7_alpha1-2.7_rc1 AND the server is configured to accept client connections with any IP-based authentication or x509 username extraction.

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 2.6.16 or later
Fixed in 2.6.16
Interim mitigation

Upgrade to OpenVPN 2.6.16 or later, or 2.7_rc2 or later, to remediate the improper source IP validation vulnerability.

Recommended fix High confidence

OpenVPN 2.6.16 or later (or a stable 2.7.x release)

  1. Backup your current OpenVPN configuration files (usually in /etc/openvpn/)
  2. Check your currently installed OpenVPN version using: openvpn --version
  3. Upgrade OpenVPN to version 2.6.16 or later. For Debian/Ubuntu: apt-get update && apt-get install openvpn. For RHEL/CentOS: yum update openvpn
  4. Verify the new version is installed: openvpn --version
  5. Restart the OpenVPN service: systemctl restart openvpn@<config-name> or service openvpn restart
  6. Verify the service is running and connections work properly
Caveat Review the OpenVPN 2.6.16 release notes for any configuration or feature changes before upgrading; most configurations should be compatible

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

Fix this in Openvpn Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-13086 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2025-13086 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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