dbcve.org
Catalyst Sd Wan ManagerApplication · Cisco

CVE-2026-20108

MEDIUM · 5.4 CVSS v3.1 Published 2026-03-25
Fix available
A fix is available. Upgrade to 20.12.5.3 / 20.15.4.2 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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 web-based management interface of Cisco Catalyst SD-WAN Manager could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface of an affected device. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of the web-based management interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected 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 confidence

This is a reflected Cross-Site Scripting (XSS) vulnerability in Cisco Catalyst SD-WAN Manager's web-based management interface. An authenticated attacker exploits insufficient input validation to inject malicious script code via a crafted link. When a victim clicks the link, the script executes in the context of the interface, allowing session hijacking or access to sensitive browser-based information.

MitigationApply the vendor patch when available. In the interim, restrict access to the web management interface to trusted users only and educate users to avoid clicking untrusted links. Consider implementing Content Security Policy (CSP) headers as a defense-in-depth measure.

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
Catalyst Sd Wan ManagerApplication
Affected:>= 20.12, < 20.12.5.3>= 20.13, < 20.15.4.2>= 20.16, < 20.18.2.1= 20.12.6

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
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 checks

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

  1. Identify Cisco Catalyst SD-WAN Manager installation
    Locate the SD-WAN Manager web interface by accessing its management URL (typically on port 443 or 8443). Confirm the product is Cisco Catalyst SD-WAN Manager by reviewing the login page banner or header.
    Affected if The product is not Cisco Catalyst SD-WAN Manager.
  2. Determine installed software version
    Log into the SD-WAN Manager web interface and navigate to the Administration > Software Updates or Help > About section to view the exact software version number.
    Affected if The installed version falls within any of these ranges: >= 20.12 and < 20.12.5.3; >= 20.13 and < 20.15.4.2; >= 20.16 and < 20.18.2.1; or equals exactly 20.12.6.
  3. Confirm web-based management interface is enabled
    Verify that the SD-WAN Manager web UI is accessible and not disabled. Check via the CLI command 'show web-management status' or review network accessibility of ports used by the web interface.
    Affected if The web management interface is enabled and reachable.
  4. Verify user authentication is configured
    Confirm that user accounts exist and authentication is required to access the web interface. Check for local users or integrated authentication (AAA) configuration via 'show running-config | include user' or similar commands.
    Affected if User authentication is required for web interface access (this is required for the vulnerability to be exploitable).

A user is affected if Cisco Catalyst SD-WAN Manager is running and its version matches one of the specified vulnerable ranges while the web management interface is accessible with authentication enabled.

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.

dbcve · scoped
Upgrade available Upgrade to 20.12.5.3 / 20.15.4.2 / 20.18.2.1 or later
Fixed in 20.12.5.320.15.4.220.18.2.1
Interim mitigation

Apply the vendor patch when available. In the interim, restrict access to the web management interface to trusted users only and educate users to avoid clicking untrusted links. Consider implementing Content Security Policy (CSP) headers as a defense-in-depth measure.

Recommended fix High confidence

20.18.2.1 or later (or 20.15.4.2 for 20.13-20.15 branches, or 20.12.5.3 for 20.12 branch)

  1. 1. Identify the currently running Cisco Catalyst SD-WAN Manager version using the web UI or CLI
  2. 2. Determine the appropriate upgrade path based on your current version: if on 20.12.x, upgrade to 20.12.5.3 (avoiding 20.12.6); if on 20.13.x-20.15.x, upgrade to 20.15.4.2 or later; if on 20.16.x-20.18.x, upgrade to 20.18.2.1 or later
  3. 3. Download the appropriate fixed software release from Cisco (requires valid service contract)
  4. 4. Review Cisco SD-WAN upgrade documentation for prerequisite steps such as taking configuration backups
  5. 5. Follow Cisco's recommended upgrade procedure for your deployment mode (standalone or cluster)
  6. 6. After upgrade, verify the new version is running and confirm the vulnerability is remediated
Caveat SD-WAN upgrades may have compatibility requirements with vManage/vBond/vEdge components; review Cisco's compatibility matrix before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Catalyst Sd Wan Manager Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,968.

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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-2026-20108 in production — separate from our analysis above.

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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