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Openvpn Access ServerApplication · Openvpn

CVE-2020-8953

CRITICAL · 9.8 CVSS v3.1 Published 2020-02-13
Fix available
A fix is available. Upgrade to 2.8.1 or later.
See remediation →
100/100
Remediation priority · Urgent
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
OpenVPN Access Server 2.8.x before 2.8.1 allows LDAP authentication bypass (except when a user is enrolled in two-factor authentication).

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 Access Server 2.8.x before 2.8.1 contains a flaw in its LDAP authentication module that allows bypass of authentication for users who are not enrolled in two-factor authentication. An attacker with knowledge of valid LDAP usernames could potentially authenticate without providing valid credentials, gaining unauthorized VPN access.

MitigationUpgrade to OpenVPN Access Server 2.8.1 or later to remediate. As an interim workaround, ensure all LDAP-authenticated users are enrolled in two-factor authentication.

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
Openvpn Access ServerApplication
Affected:>= 2.8.0, < 2.8.1

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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 OpenVPN Access Server version
    Run the command to display the installed OpenVPN Access Server version (typically 'openvpn --version' or check the admin web interface system info page)
    Affected if The installed version is 2.8.0 through 2.8.0 (any build) because this version range contains the vulnerability (versions >= 2.8.0 and < 2.8.1 are affected)
  2. Confirm LDAP authentication is configured
    Review the OpenVPN Access Server authentication settings in the admin web interface under User Management > LDAP or check the configuration files for LDAP integration settings
    Affected if LDAP authentication is enabled and the server is using LDAP to validate user credentials (the vulnerability exists in the LDAP authentication module)
  3. Determine two-factor authentication enforcement status
    Check the user authentication profile settings to see whether two-factor authentication is mandatory for all users or if it is optional or disabled
    Affected if Two-factor authentication is not enforced for LDAP-authenticated users (users not enrolled in two-factor authentication are vulnerable to the authentication bypass)
  4. Review LDAP user enrollment in two-factor authentication
    Examine the user database or admin interface to list which LDAP users have two-factor authentication enabled versus which users have not enrolled in it
    Affected if Any LDAP user accounts exist that are not enrolled in two-factor authentication (these accounts are susceptible to the bypass flaw)

You are affected if your OpenVPN Access Server version is 2.8.0, LDAP authentication is configured, and at least one LDAP user is not enrolled in two-factor authentication.

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 2.8.1 or later
Fixed in 2.8.1
Interim mitigation

Upgrade to OpenVPN Access Server 2.8.1 or later to remediate. As an interim workaround, ensure all LDAP-authenticated users are enrolled in two-factor authentication.

Recommended fix High confidence

2.8.1 or later

  1. Back up the current OpenVPN Access Server configuration and user data
  2. Update the package repository for OpenVPN Access Server
  3. Upgrade the OpenVPN Access Server package to version 2.8.1 or later
  4. Verify the upgrade was successful and test LDAP authentication functionality

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

Fix this in Openvpn Access Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,968.

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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-2020-8953 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