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[ CVE-2026-76504 · Published 30 Sep 2026 ]

Authentication bypass gives admin access to Cisco SD-WAN Manager

Exploited · CISA KEV CVSS 9.8 EPSS 2%3 agency advisoriesFix available

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-09-30
  • Critical severity: CVSS 9.8

[ Analyst view ]Is this a red alert for you?

Red alert

CISA lists it as exploited, and it gives admin access without credentials.

Red alert if
You run Cisco Catalyst SD-WAN Manager on an affected version with its interface reachable from the internet.
Can wait if
You do not use Cisco Catalyst SD-WAN, or SD-WAN Manager is only reachable from a restricted management network and you patch this week.
What it is
Cisco Catalyst SD-WAN Manager mishandles URI encoding in HTTP requests, which lets an attacker bypass authentication and use the API as the admin user. No credentials are needed.
Impact
A remote attacker can control the system that manages your SD-WAN, with full admin rights. From there they can change routing and security policy across every site the SD-WAN connects, which can cause outages or open paths into the network.

How an attack would work MITRE ATT&CK

  1. T1190 Exploit Public-Facing ApplicationThe attacker sends a crafted HTTP request to the SD-WAN Manager API.
  2. T1078 Valid AccountsThe bypass gives them a session with admin rights.
  3. T1098 Account ManipulationNew admin accounts or keys can be added to keep access.
  4. T1562 Impair DefensesSecurity policies pushed to the network edge can be weakened.

What to do

  1. Upgrade SD-WAN Manager to the fixed release in Cisco advisory cisco-sa-sdwan-webauth-xr8beuuU.
  2. Make sure the SD-WAN Manager interface and API are not reachable from the internet.
  3. Review admin accounts, API activity and recent configuration changes for anything you did not do.
  4. If you find signs of compromise, follow Cisco's and CISA's guidance and rotate the credentials and certificates SD-WAN Manager uses.
Written with AI from the sources on this page on 23 Oct 2026. Check the vendor's advisory before you act.

[ Description ]Official description

A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass authentication and gain access to the API as the admin user.

CISA: Cisco Catalyst SD-WAN Manager contains a hex encoding vulnerability that could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user due to improper handling of URI encoding in an HTTP request.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 3 Oct 2026): Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

[ Advisories ]Government CERT advisories

[ References ]References