Debian LinuxOperating system · Debian
CVE-2018-16758
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 · uneditedMissing message authentication in the meta-protocol in Tinc VPN version 1.0.34 and earlier allows a man-in-the-middle attack to disable the encryption of VPN packets.
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 confidenceTinc VPN versions 1.0.34 and earlier lack message authentication in the meta-protocol (the control channel that handles peer discovery and key exchange). This allows a man-in-the-middle attacker to intercept and modify meta-protocol messages during the handshake, potentially causing the VPN peers to disable encryption entirely for subsequent data packets.
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
Debian LinuxOperating system
= 9.0<= 1.0.34= v8CVSS 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
- None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
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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Identify installed Tinc VPN versionRun 'tincd --version' or 'tinc --version' to determine the exact version number. On Debian-based systems, also run 'dpkg -l | grep tinc' or 'apt-cache policy tinc'.Affected if The version is 1.0.34 or any earlier version.
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Verify meta-protocol is in useExamine the Tinc configuration files in /etc/tinc/<netname>/ for the host configuration files (Host =). The meta-protocol is used by default for peer discovery and key exchange between nodes.Affected if Tinc is configured with multiple peers and the meta-protocol handshake is occurring.
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Check for encryption configurationInspect the tinc.conf and host configuration files for 'Cipher' and 'Digest' options. Look for lines like 'Cipher =' and 'Digest =' to see if encryption is explicitly set.Affected if Cipher or Digest options are set to 'none' or are absent, indicating default weak or no authentication in the meta-protocol.
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Inspect running Tinc processRun 'ps aux | grep tincd' to find the running daemon, then check network connections on port 655 (default Tinc port) using 'netstat -tunap | grep 655' or 'ss -tunap | grep 655'.Affected if Tinc is running and accepting connections on the meta-protocol port without additional network isolation.
If the installed Tinc VPN version is 1.0.34 or earlier, the environment is affected by this vulnerability because the meta-protocol lacks message authentication, allowing MITM attackers to potentially disable encryption.
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 to a Tinc VPN version newer than 1.0.34 which includes proper message authentication in the meta-protocol. If upgrading is not immediately possible, restrict network access to trusted peers using firewall rules to reduce MITM exposure.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-16758 — 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-2018-16758 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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- Version or environment caveats, and links to real fixes
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