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Urgent: Cisco SD-WAN Software Vulnerability Could Let Attackers Take Control

A serious security flaw has been found in Cisco's SD-WAN Manager software that could allow attackers with certain access to take full control of the system. This matters because it could lead to unauthorised changes and disruptions in your network.

05 June 2026

Reference: CVE-2026-20245

1. What is being reported?

Cisco has identified a vulnerability in their SD-WAN Manager software that lets someone with local access and certain permissions run harmful commands as the highest-level user. This happens when the software does not properly check files uploaded to it, allowing attackers to inject commands and gain full control.

2. What this means in plain English

If an attacker gains access with specific network admin rights, they could take over your network management system, change settings, and potentially disrupt your internet connections or security. This risk is serious because it could affect how your network devices operate.

3. Could this affect a small business?

Small businesses using Cisco SD-WAN Manager with network admin access could be affected, especially if their systems are not updated. If you do not use this Cisco software or do not have network admin users who upload files, you are less likely to be impacted.

4. What to do now

  • Check if your organisation uses Cisco Catalyst SD-WAN Manager or the older SD-WAN vManage software.
  • Ask your IT provider if your current software version is vulnerable and if updates are available.
  • Apply the recommended software updates from Cisco as soon as possible to fix the vulnerability.
  • Review your network device configurations after updating to ensure no unauthorised changes were made.

5. Ask your IT provider

Can you confirm whether our Cisco SD-WAN Manager software is affected by CVE-2026-20245, and have the necessary security updates been applied?

6. Bottom line

If you use Cisco SD-WAN Manager, act quickly to update the software and protect your network from potential takeover.

Information based on CISA KEV, NVD, and reputable security news reports.

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