OpenvpnApplication
CVE-2017-7522
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 by authenticated remote attacker via sending a certificate with an embedded NULL character.
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 before 2.4.3 and 2.3.17 contain a vulnerability where an authenticated remote attacker can cause a denial of service by presenting a certificate containing an embedded NULL character. The NULL byte in the certificate triggers a parsing failure or crash in the OpenVPN service.
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
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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 OpenVPN versionRun 'openvpn --version' or check the package manager (dpkg -l openvpn, rpm -qi openvpn)Affected if Version is 2.3.16 or earlier, or 2.4.0 through 2.4.2 inclusive
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Verify client certificate authentication is enabledInspect the OpenVPN server configuration file (commonly /etc/openvpn/server.conf) and look for 'client-cert-not-required' set to false, or 'verify-x509-name' or 'cert' directives that enforce client certificate validationAffected if Client certificate authentication is required (this is the typical configuration and is the attack vector)
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Confirm TLS authentication modeCheck server.conf for 'tls-auth' directive without 'remote-cert-tls client' validation, or review if X509 certificate verification is performedAffected if Server relies on X509 certificate parsing without additional integrity checks (the vulnerability is in certificate parsing)
If the installed OpenVPN version falls within 2.3.x <= 2.3.16 or 2.4.x between 2.4.0 and 2.4.2, and client certificate authentication is enabled, the server is vulnerable to a DoS attack via crafted certificates with embedded NULL characters.
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 dataUpdate OpenVPN to version 2.4.3 or later (for 2.4.x branches) or version 2.3.17 or later (for 2.3.x branches). Alternatively, apply vendor-supplied patches if upgrading is not immediately feasible.
Fix this in Openvpn
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-7522 — 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-2017-7522 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