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OpenvpnApplication

CVE-2018-7544

CRITICAL · 9.1 CVSS v3.0 Published 2018-03-16
Fix available
A fix is available. Upgrade to after 2.4.5 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit 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 cross-protocol scripting issue was discovered in the management interface in OpenVPN through 2.4.5. When this interface is enabled over TCP without a password, and when no other clients are connected to this interface, attackers can execute arbitrary management commands, obtain sensitive information, or cause a denial of service (SIGTERM) by triggering XMLHttpRequest actions in a web browser. This is demonstrated by a multipart/form-data POST to http://localhost:23000 with a "signal SIGTERM" command in a TEXTAREA element. NOTE: The vendor disputes that this is a vulnerability. They state that this is the result of improper configuration of the OpenVPN instance rather than an intrinsic vulnerability, and now more explicitly warn against such configurations in both the management-interface documentation, and with a runtime warning

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

A detailed technical summary for this CVE is being prepared.

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:<= 2.4.5

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
High
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

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 a release after 2.4.5
Recommended fix High confidence

OpenVPN 2.4.6 or later (which includes enhanced documentation warnings and runtime warnings about unsafe management interface configurations)

  1. 1. Ensure the OpenVPN management interface is NOT exposed over TCP on any network interface other than localhost. Configure it to bind only to localhost (127.0.0.1) in the server configuration.
  2. 2. If remote management access is absolutely required, enable authentication for the management interface by setting a management password using the 'management' directive with a password file (e.g., 'management localhost 7505 /path/to/passwd').
  3. 3. Prefer Unix socket-based management interface over TCP when possible (e.g., 'management /var/run/openvpn management Unix').
  4. 4. Ensure firewall rules prevent any external access to the management interface port (default 1194 or configured port).
  5. 5. For web-based management access, implement proper authentication at the application layer and use HTTPS.

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

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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-2018-7544 in production — separate from our analysis above.

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What belongs here
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  • Version or environment caveats, and links to real fixes
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