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Sd Wan FirmwareOperating system · Cisco

CVE-2020-3385

MEDIUM · 6.5 CVSS v3.1 Published 2020-07-16
Fix available
A fix is available. Upgrade to 18.4.5 / 19.2.3 or later.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

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 · unedited
A vulnerability in the deep packet inspection (DPI) engine of Cisco SD-WAN vEdge Routers could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected system. The vulnerability is due to insufficient handling of malformed packets. An attacker could exploit this vulnerability by sending crafted packets through an affected device. A successful exploit could allow the attacker to cause the device to reboot, resulting in a DoS condition.

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 confidence

This vulnerability exists in the deep packet inspection (DPI) engine of Cisco SD-WAN vEdge Routers. The issue stems from insufficient handling of malformed packets, which allows an unauthenticated adjacent attacker to send specially crafted packets through an affected device, causing it to reboot and result in a denial of service condition.

MitigationApply the available Cisco security patch or software update for CVE-2020-3385 to all affected vEdge Router devices. Consider implementing network segmentation to limit the attack surface for adjacent attackers.

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
Sd Wan FirmwareOperating system
Affected:<= 18.3.0>= 18.4.0, < 18.4.5>= 19.2.0, < 19.2.3>= 19.3.0, < 20.1.1
Vedge Cloud RouterWeb browser
Affected:all versions

CVSS 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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device model
    Run 'show hardware' or check the device inventory to confirm the device is a Cisco vEdge Router or Vedge Cloud Router
    Affected if The device is not a vEdge Router or Vedge Cloud Router (not affected)
  2. Check the installed firmware version
    Run 'show version' on the vEdge device to obtain the current firmware version
    Affected if The firmware version is <= 18.3.0; OR >= 18.4.0 and < 18.4.5; OR >= 19.2.0 and < 19.2.3; OR >= 19.3.0 and < 20.1.1; OR the device is a Vedge Cloud Router (any version)
  3. Verify if Deep Packet Inspection is enabled
    Run 'show configuration | display xml' or check the DPI policy configuration to see if deep-packet-inspection is configured on any policy
    Affected if DPI is enabled and applied to traffic flows (the vulnerable component)
  4. Assess network exposure to adjacent attackers
    Review the interface configurations and network topology to determine if the device can receive packets from unauthenticated adjacent attackers on any data plane interface
    Affected if The device is directly accessible to unauthenticated adjacent attackers on data plane interfaces (enables exploitation)

A device is affected if it is a Cisco vEdge Router with an affected firmware version OR any Vedge Cloud Router, AND DPI is enabled, AND the device is accessible to adjacent attackers on its data plane interfaces.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 18.4.5 / 19.2.3 / 20.1.1 or later
Fixed in 18.4.519.2.320.1.1
Interim mitigation

Apply the available Cisco security patch or software update for CVE-2020-3385 to all affected vEdge Router devices. Consider implementing network segmentation to limit the attack surface for adjacent attackers.

Fix this in Sd Wan Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-3385 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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