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CVE Record

CVE-2020-3406: Cisco SD-WAN vManage Software Cross-Site Scripting Vulnerability

A 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.

MediumCVSS 6.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2020-3406 is a Cisco SD-WAN vManage web interface XSS flaw. An authenticated remote attacker could trick a user into opening a crafted link, then run script in that user’s browser session and potentially read browser-based sensitive information.

Executive priority

Treat this as a moderate-priority management-plane issue. It is not described as unauthenticated or actively exploited, but vManage controls SD-WAN operations, so patch confirmation and access restriction should be scheduled promptly.

Technical view

Cisco attributes the issue to improper validation of user-supplied input in the vManage web management interface. It is classified as CWE-79 with CVSS 3.0 score 6.4. The provided sources do not identify exact affected release ranges.

Likely exposure

Exposure is most likely where Cisco SD-WAN vManage is deployed and the management interface is reachable by authenticated users. Exact vulnerable versions are not included in the source bundle; teams must confirm against Cisco’s advisory.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. Cisco describes a crafted-link XSS scenario requiring an authenticated remote attacker and impact limited to browser-session script execution and browser-based information access.

Researcher notes

Key gaps are exact affected versions, fixed releases, and exploit maturity beyond Cisco’s description. Use Cisco’s advisory as the authoritative source before asserting exposure or remediation status.

Mitigation direction

  • Review Cisco’s advisory for affected and fixed vManage releases.
  • Upgrade Cisco SD-WAN vManage according to Cisco’s published guidance.
  • Restrict vManage management interface access to trusted administrative networks.
  • Reinforce phishing-resistant handling of management-interface links.
  • Monitor vManage administrative sessions for unusual browser-driven actions.

Validation and detection

  • Inventory all Cisco SD-WAN vManage instances and exposed management interfaces.
  • Compare installed vManage versions against Cisco’s advisory.
  • Confirm administrative access paths require authentication and trusted network access.
  • Review logs for suspicious authenticated activity around vManage web sessions.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2020-3406 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.4 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.4CVSS 3.0MediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N3.12.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

6.4Medium
CVSS 3.0 vector shape for CVE-2020-3406Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco SD-WAN vManagen/aListed
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-79 · source CWE mapping

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs