Sd Wan FirmwareOperating system · Cisco
CVE-2020-3406
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 vulnerability in the web-based management interface of the Cisco SD-WAN vManage Software could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface. The vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or access sensitive, browser-based information.
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 confidenceCross-site scripting (XSS) vulnerability in Cisco SD-WAN vManage web-based management interface due to improper validation of user-supplied input. An authenticated remote attacker can inject malicious scripts via crafted links, potentially executing arbitrary code in the context of the interface or accessing sensitive browser-based information.
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
<= 19.2.2CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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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Confirm Cisco SD-WAN vManage is deployedIdentify if your environment includes Cisco SD-WAN vManage by reviewing network architecture documentation, asset inventory, or checking for vManage-related hostnames/IPs in your networkAffected if vManage is present in your environment and the version is unclear or <= 19.2.2
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Determine the installed vManage firmware versionAccess the vManage admin console or use the CLI command 'show version' on the vManage device to retrieve the firmware version numberAffected if The installed version is 19.2.2 or any version lower than 19.2.2
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Verify the web-based management interface is enabledConfirm that the vManage web UI (typically on port 443 or 8443) is accessible and operational by attempting to reach the login page or checking service statusAffected if The vManage web interface is exposed and the firmware version is <= 19.2.2
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Assess authentication requirementsNote that this XSS requires an authenticated attacker; review whether user accounts exist in vManage and whether the web interface permits user loginAffected if The web interface allows authentication and the firmware version is <= 19.2.2
You are affected if your environment runs Cisco SD-WAN vManage with firmware version 19.2.2 or lower and the web-based management interface is accessible to authenticated users.
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 dataApply the Cisco patch when available. Until then, educate users about not clicking untrusted links within the vManage interface and consider network segmentation to limit exposure.
Fix this in Sd Wan Firmware
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3406 — 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-2020-3406 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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