CVE-2021-1272
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 session validation feature of Cisco Data Center Network Manager (DCNM) could allow an unauthenticated, remote attacker to bypass access controls and conduct a server-side request forgery (SSRF) attack on a targeted system. This vulnerability is due to insufficient validation of parameters in a specific HTTP request by an attacker. An attacker could exploit this vulnerability by sending a crafted HTTP request to an authenticated user of the DCNM web application. A successful exploit could allow the attacker to bypass access controls and gain unauthorized access to the Device Manager application, which provides access to network devices managed by the 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 vulnerability in Cisco DCNM's session validation feature allows an unauthenticated remote attacker to bypass access controls by sending a crafted HTTP request with insufficiently validated parameters, enabling server-side request forgery (SSRF) and unauthorized access to the Device Manager application.
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< 11.5\(1\)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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 DCNM versionLog into the DCNM web interface and navigate to the About or Administration page, or run 'show version' via CLI if you have appliance access, to retrieve the exact software version numberAffected if The version displayed is below 11.5(1)
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Verify the DCNM web management interface is accessibleConfirm that the DCNM web interface (typically ports 80/443 or the Device Manager application) is reachable on the networkAffected if The management interface is exposed and responds to HTTP/HTTPS requests
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Check for active session validation on HTTP endpointsReview DCNM configuration for session validation settings, typically found in the web server or security settings section of the administration consoleAffected if Session validation is enabled but the version is unpatched
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Confirm Device Manager application accessibilityAttempt to access the Device Manager application component via its URL path (such as /dm or similar web endpoint) without authenticationAffected if The application is reachable and responds without proper authentication
If the installed Cisco DCNM version is below 11.5(1) and the web-based management or Device Manager interface is network-accessible, the environment is affected by this vulnerability.
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 data11.5
Apply the vendor patch from Cisco for DCNM. If immediate patching is not possible, restrict network access to the DCNM management interfaces and monitor for suspicious HTTP requests.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1272 — 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-2021-1272 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
- No weaponised exploit code, or anything meant to cause harm
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