CVE-2017-7935
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 · uneditedA Resource Exhaustion issue was discovered in Phoenix Contact GmbH mGuard firmware versions 8.3.0 to 8.4.2. An attacker may compromise the device's availability by performing multiple initial VPN requests.
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 confidencePhoenix Contact mGuard firmware versions 8.3.0 through 8.4.2 contain a resource exhaustion vulnerability where an attacker can repeatedly send initial VPN requests to consume device resources, causing denial of service and preventing legitimate VPN connections.
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= 8.3.0= 8.3.1= 8.3.2= 8.4.0= 8.4.1= 8.4.2CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/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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Identify mGuard firmware versionLog into the mGuard web interface and navigate to System > Status or Device Information to view the installed firmware version. Alternatively, use the CLI command 'show version' or check the /etc/version file if SSH access is available.Affected if The displayed firmware version is 8.3.0, 8.3.1, 8.3.2, 8.4.0, 8.4.1, or 8.4.2.
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Verify VPN functionality is enabledAccess mGuard configuration and check the IPsec/VPN settings page. Look for active VPN tunnels, IPsec profiles, or remote access VPN configurations.Affected if VPN or IPsec is enabled and configured on the device.
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Check network exposure of VPN portsReview firewall or network configuration to determine if VPN ports (500/UDP, 4500/UDP for IPsec) are accessible from external or untrusted networks. Use port scanning from an external location or review access control lists.Affected if VPN ports are exposed to the internet or untrusted network segments.
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Inspect system resources and logsCheck system monitoring for high CPU, memory, or connection limits. Review mGuard system logs for error messages related to VPN connection failures, resource exhaustion, or connection rejections.Affected if Logs show connection errors, resource warnings, or the device exhibits unusual slowness during VPN operations.
You are affected if your mGuard firmware version falls within 8.3.0 to 8.4.2, VPN is enabled, and the device or its VPN ports are accessible to network attackers who could exhaust resources via repeated connection attempts.
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 mGuard firmware to version 8.4.3 or later. If immediate patching is not feasible, implement network-level rate limiting or firewall rules to restrict VPN connection attempts from untrusted sources.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-7935 — 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-2017-7935 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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