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Catalyst Sd Wan ManagerApplication · Cisco

CVE-2021-1546

MEDIUM · 5.5 CVSS v3.1 Published 2021-09-23
Fix available
A fix is available. Upgrade to 20.4.2 / 20.5.2 or later.
See remediation →
57/100
Remediation priority · Elevated
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 CLI of Cisco SD-WAN Software could allow an authenticated, local attacker to access sensitive information. This vulnerability is due to improper protections on file access through the CLI. An attacker could exploit this vulnerability by running a CLI command that targets an arbitrary file on the local system. A successful exploit could allow the attacker to return portions of an arbitrary file, possibly resulting in the disclosure of sensitive information.

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

Cisco SD-WAN Software contains a local file inclusion vulnerability in its CLI that allows authenticated attackers to read arbitrary files by running specific CLI commands. The vulnerability stems from insufficient access controls on file operations within the CLI interface, enabling disclosure of sensitive system files.

MitigationApply Cisco's patch for CVE-2021-1546 when available. Restrict CLI access to trusted administrators only and monitor for unusual file access patterns via CLI commands.

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
Affected:>= 18.4, < 20.4.2>= 20.6, < 20.6.1
Sd Wan Vbond OrchestratorApplication
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1
Sd Wan VmanageApplication
Affected:>= 20.5, < 20.5.2
Vsmart Controller FirmwareOperating system
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1
Vedge 100 FirmwareOperating system
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1
Vedge 1000 FirmwareOperating system
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1
Vedge 100b FirmwareOperating system
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1
Vedge 100m FirmwareOperating system
Affected:>= 18.4, < 20.4.2>= 20.5, < 20.5.2>= 20.6, < 20.6.1

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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

  1. Identify the installed product and version
    Use CLI commands such as 'show version' or 'show system information' to determine the Cisco SD-WAN component type and its running software version
    Affected if The installed version falls within any of these ranges: >= 18.4 and < 20.4.2; >= 20.5 and < 20.5.2; >= 20.6 and < 20.6.1; or for vManage specifically >= 20.5 and < 20.5.2
  2. Confirm CLI access is available
    Verify that the CLI interface is accessible by attempting to log in or checking the management interface configuration
    Affected if CLI access is enabled and reachable (the vulnerability requires authenticated CLI access to be exploited)
  3. Review user access controls on CLI
    Examine CLI user accounts and privilege levels using 'show users' or 'show running-config | include user' commands
    Affected if Multiple user accounts exist or users with lower privilege levels have CLI access (the vulnerability stems from insufficient access controls)
  4. Audit recent CLI command history
    Review CLI command logs or audit trails for unusual file read operations, if logging is configured
    Affected if Logs show requests for system files outside normal operations, such as /etc/passwd or configuration files

You are affected if your installed Cisco SD-WAN product version falls within the vulnerable ranges AND the CLI interface is accessible to authenticated users, because the vulnerability allows authenticated attackers to read arbitrary files via specific CLI commands.

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.

dbcve · scoped
Upgrade available Upgrade to 20.4.2 / 20.5.2 / 20.6.1 or later
Fixed in 20.4.220.5.220.6.1
Interim mitigation

Apply Cisco's patch for CVE-2021-1546 when available. Restrict CLI access to trusted administrators only and monitor for unusual file access patterns via CLI commands.

Recommended fix High confidence

20.4.2, 20.5.2, or 20.6.1 (specific version depends on product and current branch)

  1. 1. Identify the specific Cisco SD-WAN product (vManage, vBond, vSmart, or vEdge) running in your environment using the CLI command 'show version'
  2. 2. Determine the current installed version of the software
  3. 3. Based on the product type, upgrade to the minimum fixed release: For vManage, upgrade to 20.5.2 or later; For vBond, upgrade to 20.4.2, 20.5.2, or 20.6.1 depending on your current branch; For vSmart and all vEdge devices (100, 1000, 100b, 100m), upgrade to 20.4.2, 20.5.2, or 20.6.1 depending on your current branch; For Catalyst SD WAN Manager, upgrade to 20.4.2 or 20.6.1
  4. 4. Download the appropriate software image from Cisco.com (requires valid service contract)
  5. 5. Follow standard Cisco SD-WAN upgrade procedures, typically using the 'request software install' CLI command
  6. 6. After upgrade, verify the fix by confirming the version matches or exceeds the fixed release
  7. 7. Verify the vulnerability is remediated by attempting the vulnerable command - it should now be properly restricted
Caveat Standard SD-WAN upgrade downtime required; ensure valid backup and follow Cisco upgrade documentation; may require compatibility checks with other SD-WAN components

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Catalyst Sd Wan Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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-2021-1546 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