Cisco Catalyst SD-WAN Manager up to 18.4.3 API Authentication authentication bypass

Summaryinfo

A vulnerability was found in Cisco Catalyst SD-WAN Manager. It has been classified as very critical. This impacts an unknown function of the component API Authentication. The manipulation leads to authentication bypass. This vulnerability is referenced as CVE-2026-76504. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Cisco Catalyst SD-WAN Manager and classified as very critical. This issue affects an unknown code block of the component API Authentication. The manipulation with an unknown input leads to a authentication bypass vulnerability. Using CWE to declare the problem leads to CWE-288. A product requires authentication, but the product has an alternate path or channel that does not require authentication. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at sec.cloudapps.cisco.com. The identification of this vulnerability is CVE-2026-76504 since 08/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/30/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Network Management Software

Vendor

• Cisco

Name

• Catalyst SD-WAN Manager

Version

• 17.2.4
• 17.2.5
• 17.2.6
• 17.2.7
• 17.2.8
• 17.2.9
• 17.2.10
• 18.2.0
• 18.3.0
• 18.3.1
• 18.3.1.1
• 18.3.3
• 18.3.3.1
• 18.3.4
• 18.3.5
• 18.3.6
• 18.3.6.1
• 18.3.7
• 18.3.8
• 18.4.0
• 18.4.0.1
• 18.4.1
• 18.4.3

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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