Catalyst Sd Wan ManagerApplication · Cisco
CVE-2026-20126
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 Cisco Catalyst SD-WAN Manager could allow an authenticated, local attacker with low privileges to gain root privileges on the underlying operating system. This vulnerability is due to an insufficient user authentication mechanism in the REST API. An attacker could exploit this vulnerability by sending a request to the REST API of the affected system. A successful exploit could allow the attacker to gain root privileges on the underlying operating system.
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 confidenceThis is a privilege escalation vulnerability in Cisco Catalyst SD-WAN Manager's REST API where low-privilege authenticated users can gain root access due to insufficient authentication validation. The attacker sends specially crafted requests to the REST API to bypass privilege checks.
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
< 20.9.8.2>= 20.11, < 20.12.5.3>= 20.13, < 20.15.4.2>= 20.16, < 20.18.2.1= 20.12.6CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 the installed Cisco Catalyst SD-WAN Manager versionAccess the SD-WAN Manager admin interface or use the CLI command 'show version' or check the About page in the web UI to determine the running software versionAffected if The installed version falls into any of these ranges: < 20.9.8.2; >= 20.11 and < 20.12.5.3; = 20.12.6; >= 20.13 and < 20.15.4.2; >= 20.16 and < 20.18.2.1
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Confirm REST API is accessibleAttempt to reach the REST API endpoint (typically https://<sdwan-manager-ip>/dataservice) using a web browser or curl command to verify the API is exposedAffected if The REST API responds to requests and is accessible from the network where low-privilege users operate
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Enumerate REST API users and their privilege levelsUse the SD-WAN Manager administrative interface or API queries to list all users with REST API access and review their assigned privilege rolesAffected if There exist users with authenticated API access who hold privileges below administrator level (such as operator, viewer, or custom low-privilege roles)
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Review audit logs for privilege escalation indicatorsExamine SD-WAN Manager logs for API requests that include unusual parameter patterns or requests to administrative endpoints made by non-administrator accountsAffected if Logs show API calls from low-privilege users to endpoints that should require elevated permissions, or patterns indicative of bypass attempts
You are affected if your SD-WAN Manager version is within the vulnerable ranges AND the REST API is accessible to authenticated users with less than full administrator privileges.
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.
dbcve · scoped20.9.8.220.12.5.320.15.4.2
Apply the Cisco vendor patch when available. Until then, restrict REST API access to only necessary administrative personnel and monitor for unusual API request patterns.
20.18.2.1 or later (select the appropriate fixed version for your branch: 20.9.8.2, 20.12.5.3, 20.15.4.2, or 20.18.2.1)
- 1. Identify the current version of Cisco Catalyst SD-WAN Manager by accessing the controller UI or using the CLI command 'show version'
- 2. Determine which version branch your current installation falls into based on the affected version ranges
- 3. Plan maintenance window as upgrade will require system downtime
- 4. Backup current configuration and verify backup integrity before proceeding
- 5. Download the appropriate fixed version from Cisco (20.9.8.2 or later for 20.9.x, 20.12.5.3 or later for 20.11.x-20.12.x, 20.15.4.2 or later for 20.13.x-20.15.x, 20.18.2.1 or later for 20.16.x-20.18.x)
- 6. Upload the upgrade image to the SD-WAN Manager via the administration interface
- 7. Initiate the upgrade process following Cisco's standard upgrade procedure
- 8. After upgrade completes, verify the new version is running using 'show version'
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Catalyst Sd Wan Manager
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 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 $2,512.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20126 — 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-2026-20126 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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- Version or environment caveats, and links to real fixes
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