dbcve.org
Ios XeOperating system · Cisco

CVE-2021-1433

HIGH · 8.1 CVSS v3.1 Published 2021-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
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
A vulnerability in the vDaemon process in Cisco IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected device. This vulnerability is due to insufficient bounds checking when the device processes traffic. An attacker could exploit this vulnerability by sending crafted traffic to the device. The attacker must have a man-in-the-middle position between Cisco vManage and an associated device that is running an affected version of Cisco IOS XE SD-WAN Software. An exploit could allow the attacker to conduct a controllable buffer overflow attack (and possibly execute arbitrary commands as the root user) or cause a device reload, resulting in a denial of service (DoS) condition.

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 confidence

Buffer overflow vulnerability in the vDaemon process of Cisco IOS XE SD-WAN Software due to insufficient bounds checking when processing traffic. An unauthenticated remote attacker with a man-in-the-middle position between Cisco vManage and affected devices can send crafted traffic to trigger a controllable buffer overflow, potentially executing arbitrary commands as root, or cause device reload (DoS).

MitigationApply Cisco-provided software updates for Cisco IOS XE SD-WAN Software. Until patched, mitigate by securing the management path between vManage and edge devices (VPN isolation, encrypted tunnels) to reduce MITM attack surface.

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 XeOperating system
Affected:= 3.15.1xbs= 3.15.2xbs= 16.12.1= 16.12.1a= 16.12.1c= 16.12.1s= 16.12.1t= 16.12.1w= 16.12.1x= 16.12.1y= 16.12.1z= 16.12.1za

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/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 checks

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

  1. Confirm Cisco IOS XE SD-WAN is deployed
    Run 'show sdwan version' or 'show version' to identify if the device runs IOS XE with SD-WAN capabilities
    Affected if Device does not run IOS XE SD-WAN software (the vulnerability only applies to SD-WAN deployments)
  2. Identify the IOS XE software version
    Execute 'show version' and locate the version string in the output (e.g., 16.12.1, 16.12.1a, etc.)
    Affected if Version matches any of: 3.15.1xbs, 3.15.2xbs, 16.12.1, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.1t, 16.12.1w, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1za
  3. Verify vDaemon process is running
    Run 'show process cpu history' or 'show processes' and look for the vDaemon process in the output
    Affected if vDaemon process is active on the device (this is the vulnerable component)
  4. Check management network exposure
    Review network configuration between vManage and edge devices: examine interface bindings, VPN tunnel status, and routing tables using 'show sdwan interface' and 'show sdwan tunnel'
    Affected if Management traffic between vManage and devices traverses unencrypted or poorly isolated paths, enabling MITM positioning

Device is affected if it runs one of the listed IOS XE SD-WAN versions with vDaemon active and has vulnerable management network exposure to MITM attacks.

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 Cisco-provided software updates for Cisco IOS XE SD-WAN Software. Until patched, mitigate by securing the management path between vManage and edge devices (VPN isolation, encrypted tunnels) to reduce MITM attack surface.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,840
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,144.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-1433 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-1433 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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