CVE-2020-22844
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 buffer overflow in Mikrotik RouterOS 6.47 allows unauthenticated attackers to cause a denial of service (DOS) via crafted SMB 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 · high confidenceA buffer overflow vulnerability exists in Mikrotik RouterOS version 6.47 within the SMB service implementation. Unauthenticated remote attackers can send specially crafted SMB packets that overflow a buffer, causing the device to crash and resulting in denial of 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= 6.47CVSS 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 RouterOS versionAccess the device via SSH, WinBox, or WebFig and run the command `/system resource print` or check the System > Resources menu in the GUI to view the installed RouterOS version.Affected if The displayed version number is exactly 6.47 (the only affected version for this CVE).
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Confirm SMB service is enabledRun `/ip smb print` in the RouterOS CLI or check the IP > SMB menu in WinBox/WebFig to see if the SMB service is turned on.Affected if The SMB service shows as enabled (the vulnerability only affects systems with SMB actively running).
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Verify SMB configurationRun `/ip smb print` to check the `interfaces` binding and whether SMB is listening on all interfaces or only specific ones.Affected if SMB is bound to a wide network interface (such as 'all' or 'bridge' that includes WAN-facing interfaces) rather than only LAN-only interfaces.
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Check firewall rules exposing SMBRun `/ip firewall filter print` and look for rules allowing SMB traffic (ports TCP/445 and TCP/139) from untrusted networks, especially rules with `in-interface` pointing to WAN interfaces.Affected if There are firewall rules permitting SMB access from external/untrusted IP addresses or WAN interfaces.
The environment is affected only if the device runs exactly RouterOS version 6.47 AND has the SMB service enabled AND SMB is accessible from untrusted networks (either directly via WAN interface binding or through permissive firewall rules).
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 RouterOS to a patched version beyond 6.47, or disable the SMB service if not required, or restrict SMB access to trusted networks via firewall rules to limit attack surface.
- Consultation3.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-22844 — 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-2020-22844 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
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