Catalyst CenterApplication · Cisco
CVE-2021-1134
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 Cisco Identity Services Engine (ISE) integration feature of the Cisco DNA Center Software could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data. The vulnerability is due to an incomplete validation of the X.509 certificate used when establishing a connection between DNA Center and an ISE server. An attacker could exploit this vulnerability by supplying a crafted certificate and could then intercept communications between the ISE and DNA Center. A successful exploit could allow the attacker to view and alter sensitive information that the ISE maintains about clients that are connected to the network.
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 · moderate confidenceA vulnerability exists in Cisco DNA Center's ISE integration feature due to incomplete X.509 certificate validation. An unauthenticated remote attacker can supply a crafted certificate to intercept communications between DNA Center and ISE servers, allowing viewing and alteration of sensitive network client 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
Catalyst CenterApplication
< 2.2.2.1CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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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Identify the installed Cisco DNA Center / Catalyst Center versionAccess the Cisco DNA Center UI and navigate to Help > About, or use the CLI command 'show version' to retrieve the exact version numberAffected if The installed version is below 2.2.2.1 (e.g., 2.1.x, 2.0.x, 1.x)
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Verify ISE integration is configuredLog into DNA Center as an administrator and navigate to Design > Network Settings > ISE or System > Settings > External Services > ISE to check if any ISE servers are definedAffected if One or more ISE servers are configured and connected to DNA Center
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Check certificate validation settings for ISE connectionsIn the DNA Center ISE integration settings, examine the certificate trust configuration - look for options related to certificate chain validation, hostname verification, and CA trust settingsAffected if Certificate validation is disabled, set to 'Allow all', or certificate chain/trust validation is not explicitly enforced
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Inspect active ISE connection statusNavigate to Operations > Tasks or the ISE dashboard to view current connections and any certificate-related warnings or errors for ISE integrationsAffected if Connections to ISE are active without proper certificate validation warnings being blocked
You are affected if DNA Center/Catalyst Center version is below 2.2.2.1 AND ISE integration is configured with incomplete or disabled X.509 certificate validation.
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 data2.2.2.1
Implement proper X.509 certificate chain validation including subject verification, hostname checking, and certificate chain trust validation. Consider certificate pinning for ISE connections and ensure only certificates from trusted CAs are accepted.
Fix this in Catalyst Center
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1134 — 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-2021-1134 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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