OpenvpnApplication
CVE-2017-7520
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 · uneditedOpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to denial-of-service and/or possibly sensitive memory leak triggered by man-in-the-middle attacker.
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 confidenceOpenVPN versions before 2.4.3 and before 2.3.17 contain a vulnerability where a man-in-the-middle attacker can trigger a denial-of-service condition and potentially leak sensitive memory contents. The attack exploits how OpenVPN processes certain network interactions during the connection handshake phase, allowing an attacker positioned between the client and server to inject malicious packets that cause memory corruption or exhaustion.
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
<= 2.3.16= 2.4.0= 2.4.1= 2.4.2CVSS 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:3.0/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 checksWork through these to decide whether this CVE applies to you.
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Verify OpenVPN is installedRun 'openvpn --version' or check your package manager (e.g., 'dpkg -l openvpn', 'rpm -qa openvpn')Affected if OpenVPN is not installed or the command fails - not applicable
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Determine installed OpenVPN versionExecute 'openvpn --version' and note the exact version number displayed (e.g., 2.4.2, 2.3.16)Affected if Unable to retrieve version - manual investigation required
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Compare version against vulnerable 2.4.x rangeIf version starts with 2.4, check if it is 2.4.0, 2.4.1, or 2.4.2 - these versions are affectedAffected if Version is 2.4.0, 2.4.1, or 2.4.2 - you are vulnerable
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Compare version against vulnerable 2.3.x rangeIf version starts with 2.3, check if it is 2.3.16 or earlier - any version <= 2.3.16 is affectedAffected if Version is 2.3.16 or lower (e.g., 2.3.15, 2.3.14) - you are vulnerable
You are affected if your installed OpenVPN version is 2.4.0, 2.4.1, 2.4.2, or any 2.3.x version 2.3.16 or lower.
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 to version 2.4.3 or later (or 2.3.17 or later for the 2.3.x branch) to resolve this vulnerability. Additionally, ensure proper network segmentation and authentication controls to reduce the likelihood of man-in-the-middle attacks.
Fix this in Openvpn
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-7520 — 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-2017-7520 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