Catalyst Sd Wan ManagerApplication · Cisco
CVE-2026-20128
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 Data Collection Agent (DCA) feature of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to gain DCA user privileges on an affected system. This vulnerability is due to the presence of a credential file for the DCA user on an affected system. An attacker could exploit this vulnerability by sending a crafted HTTP request and reading the file that contains the DCA password from that affected system. A successful exploit could allow the attacker to access another affected system and gain DCA user privileges. Note: Cisco Catalyst SD-WAN Manager releases 20.18 and later are not affected by this vulnerability.
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 confidenceThe vulnerability exists in Cisco Catalyst SD-WAN Manager's Data Collection Agent (DCA) feature where a credential file containing the DCA user's password is stored on the system and accessible via a crafted HTTP request. An unauthenticated remote attacker can read this file to obtain the DCA password and then authenticate as the DCA user to gain privileged access.
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>= 20.10, < 20.12.5.3>= 20.13, < 20.15.4.2>= 20.16, < 20.18= 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
- High
- Privileges
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/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 Cisco Catalyst SD-WAN Manager versionAccess the administration interface or use CLI command 'show version' to retrieve the installed software version. Compare this against the affected ranges: < 20.9.8.2; >= 20.10 and < 20.12.5.3; >= 20.13 and < 20.15.4.2; >= 20.16 and < 20.18; = 20.12.6Affected if The installed version falls within any of these ranges, the system is potentially vulnerable
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Verify if HTTP/HTTPS management interface is externally accessibleCheck network firewall rules or perform an external port scan from an untrusted network to confirm whether TCP ports 443 (HTTPS) or 80 (HTTP) on the SD-WAN Manager management IP are reachable from outside the trusted networkAffected if The management interface is reachable from untrusted networks, the vulnerability is remotely exploitable
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Confirm DCA (Data Collection Agent) feature is configuredLog into the SD-WAN Manager administrative console and navigate to the Data Collection Agent settings, or review configuration files for DCA-related entriesAffected if DCA is enabled or configured on the system, the credential file targeted by this vulnerability exists and may be exposed
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Inspect HTTP access logs for anomalous requestsReview web server access logs on the SD-WAN Manager for requests to credential file paths or unusual patterns targeting the DCA configurationAffected if Evidence exists of crafted HTTP requests attempting to access DCA credential files, the system has likely been exploited
If the installed version is within the affected ranges AND the management interface is externally accessible, the environment is vulnerable to unauthenticated credential disclosure via crafted HTTP requests.
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
Upgrade to Cisco Catalyst SD-WAN Manager release 20.18 or later, as these releases are not affected by the vulnerability. If upgrading is not immediately feasible, implement network-level access controls to restrict unauthorized access to the vulnerable HTTP endpoint.
20.18 or later
- Identify the current installed version of Cisco Catalyst SD-WAN Manager
- Determine which version branch the current installation falls into (20.9.x, 20.10-20.12.x, 20.13-20.15.x, or 20.16-20.17.x)
- For versions < 20.9.8.2: upgrade to 20.9.8.2 or later (preferably to 20.18 or later)
- For versions >= 20.10 and < 20.12.5.3: upgrade to 20.12.5.3 or later (preferably to 20.18 or later)
- For versions >= 20.13 and < 20.15.4.2: upgrade to 20.15.4.2 or later (preferably to 20.18 or later)
- For versions >= 20.16 and < 20.18: upgrade to 20.18 or later
- Verify the upgrade was successful and the DCA credential file vulnerability is no longer present
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Catalyst Sd Wan Manager
Exploited in the wild — priority engagement
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,680.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20128 — 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-2026-20128 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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