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Ios Xe Sd WanOperating system · Cisco

CVE-2021-1273

HIGH · 8.6 CVSS v3.1 Published 2021-01-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

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 confidence

Multiple vulnerabilities in Cisco SD-WAN products allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against affected devices. The vulnerabilities likely involve improper input validation or resource management in the SD-WAN software stack, enabling attackers to crash or saturate the device without authentication.

MitigationApply the relevant Cisco SD-WAN patches or updates as specified in the Cisco advisory. Implement network segmentation and access controls to limit exposure to unauthenticated attackers until patches are applied.

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
Ios Xe Sd WanOperating system
Affected:all versions
Sd Wan FirmwareOperating system
Affected:= 18.3.5= 18.3.8= 18.4.1= 18.4.4= 18.4.5= 19.2.0= 19.2.1= 19.2.2= 19.2.99= 20.1.0
Sd Wan Vsmart Controller FirmwareOperating system
Affected:all versions
Catalyst Sd Wan ManagerApplication
Affected:all versions
Sd Wan Vbond OrchestratorApplication
Affected:all versions

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
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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 checks

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

  1. Identify the SD-WAN product type
    Log into the device CLI or management interface and run 'show version' or check the SD-WAN Manager console to determine which SD-WAN component is running (IOS XE SD-WAN, SD-WAN Firmware, vSmart Controller, vBond Orchestrator, or Catalyst SD-WAN Manager)
    Affected if The device is running any Cisco SD-WAN component (IOS XE SD-WAN, SD-WAN Firmware, vSmart, vBond, or SD-WAN Manager)
  2. Check Cisco IOS XE SD-WAN version
    Run 'show version' on the IOS XE SD-WAN device and note the IOS XE release number
    Affected if The device is running any version of Cisco IOS XE SD-WAN (all versions are affected)
  3. Check SD-WAN Firmware version
    Run 'show sdwan version' or access the vManage/vSmart/vBond CLI and check the firmware release using 'show version' or 'about' command
    Affected if The firmware version matches: 18.3.5, 18.3.8, 18.4.1, 18.4.4, 18.4.5, 19.2.0, 19.2.1, 19.2.2, 19.2.99, or 20.1.0
  4. Check vSmart/vBond/SD-WAN Manager version
    Access the controller CLI or SD-WAN Manager interface and run 'show version' or check the About section in the web UI
    Affected if The device is running any version of Cisco SD-WAN vSmart Controller, vBond Orchestrator, or Catalyst SD-WAN Manager (all versions are affected)
  5. Verify network exposure of SD-WAN interfaces
    Review the device configuration for 'wanip' or interface bindings using 'show sdwan interface' or check access control lists; determine if management or SD-WAN control plane interfaces are reachable from untrusted networks
    Affected if SD-WAN management or control interfaces are exposed to untrusted networks without authentication barriers

If the environment contains any Cisco IOS XE SD-WAN, SD-WAN Firmware (listed versions), vSmart Controller, vBond Orchestrator, or Catalyst SD-WAN Manager, and these interfaces are network-accessible, the environment is affected by this CVE.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco SD-WAN patches or updates as specified in the Cisco advisory. Implement network segmentation and access controls to limit exposure to unauthenticated attackers until patches are applied.

Fix this in Ios Xe Sd Wan Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,160
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Scan for this in your stack

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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-2021-1273 in production — separate from our analysis above.

No notes yet

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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