CVE-2020-28393
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 · uneditedAn unauthenticated remote attacker could create a permanent denial-of-service condition by sending specially crafted OSPF packets. Successful exploitation requires OSPF to be enabled on an affected device on the SCALANCE XM-400, XR-500 (All versions prior to v6.4).
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 confidenceA denial-of-service vulnerability exists in Siemens SCALANCE XM-400 and XR-500 network switches where specially crafted OSPF routing protocol packets from an unauthenticated remote attacker can cause a permanent DoS condition. Successful exploitation requires OSPF to be enabled on the affected device.
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< 6.4< 6.4< 6.4< 6.4< 6.4< 6.4< 6.4< 6.4CVSS 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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Identify device modelLog into the SCALANCE device web interface or CLI and locate the device model name (e.g., XM-400, XR-528) in the system information or device status sectionAffected if Device model is one of: Scalance XM-400, XR-524, XR-526, XR-528, XR-552, XM416-4c, XM408-8c, or XM408-4c
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Check installed firmware versionAccess the device web interface under System > Firmware or use the CLI command to display firmware version (commonly 'show version' or via web UI device info)Affected if Firmware version is lower than 6.4 (e.g., 6.2, 6.3, etc.)
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Verify OSPF routing protocol statusNavigate to the routing or OSPF configuration section in the device web interface or CLI (commonly found under Layer 3 > OSPF or via 'show ip ospf' command) and check if OSPF is enabledAffected if OSPF is enabled and active on any interface (this is the required condition for exploitation)
User is affected if the device is a SCALANCE XM-400 or XR-500 series model running firmware version below 6.4 AND has OSPF protocol enabled on any interface.
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 data6.4
Update SCALANCE XM-400/XR-500 devices to firmware version v6.4 or later. If immediate patching is not possible, consider disabling OSPF or implementing network segmentation to limit exposure.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-28393 — 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-2020-28393 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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- 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
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