OpenvpnApplication
CVE-2020-20813
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 · uneditedControl Channel in OpenVPN 2.4.7 and earlier allows remote attackers to cause a denial of service via crafted reset packet.
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 confidenceOpenVPN versions 2.4.7 and earlier contain a vulnerability in the Control Channel where specially crafted reset packets sent by remote attackers can trigger a denial of service condition, causing the VPN service to become unavailable.
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
<= 2.4.7CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Determine installed OpenVPN versionRun 'openvpn --version' or 'openvpn --help' from command line, or check via package manager (rpm -qa | grep openvpn or dpkg -l | grep openvpn)Affected if Version number displayed is 2.4.7 or lower
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Confirm OpenVPN service is runningCheck for running openvpn process (tasklist on Windows, ps on Linux) or check service status (systemctl status openvpn or service openvpn status)Affected if OpenVPN process is active and serving connections
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Verify Control Channel configuration is in useReview OpenVPN configuration file (typically /etc/openvpn/server.conf on Linux or config.ovpn on Windows) for presence of 'tls-auth' or 'tls-crypt' directives, or simply confirm standard tunnel mode is configuredAffected if Standard OpenVPN tunnel configuration is active (Control Channel is default)
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Check network exposureReview firewall rules or network binding configuration to determine if OpenVPN port (default 1194/UDP or TCP) is accessible from untrusted networksAffected if OpenVPN port is exposed to external/network attackers who could send malicious reset packets
User is affected if OpenVPN version 2.4.7 or earlier is installed AND the service is running with network exposure to potential remote attackers.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade OpenVPN installations to a version newer than 2.4.7 to remediate this vulnerability. Additionally, network-level filtering of unexpected reset packets may provide temporary mitigation.
Fix this in Openvpn
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-20813 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-20813 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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